The Bible has revealed to Christians all that we need to know about Spiritual Warfare mainly in Ephesians 6:10-18. Contrary to current popular practice of many churches and Christians, spiritual warfare is not limited to prayers alone as it's outline in Ephesians 6:10-18 shows.
BATTLEGROUND OF SPIRITUAL WARFARE
However before studying Ephesians 6:10-18 for in depth understanding of spiritual warfare it on also very important to know and understand that the Bible tells us that spiritual warfare takes in the MIND according to 2 COR 10:3-6 "For though we walk in the flesh,we do not war in the flesh: For the weapons of our warfare are not carnal,but mighty through God to the pulling down of strong holds; Casting down imaginations,and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ; And having in readiness to revenge all disobedience,when your obedience is fulfilled". Obviously, the Mind is where the Spirit, Soul and body of a man meets, therefore the real personality of a man is not actually the flesh we see but the mind of that man from where all his conduct and character emanates from, according to PROV 4:23 "Keep thy heart with all diligence ;for out of it are the issues of life". So the first attack of Satan and his cohorts against any man is to mind. This attack is called temptation. Biblical examples abound that shows that spiritual warfare first takes place in the Mind as can be seen in the encounter of Eve and the Serpent in GEN 3:1-6 where Eve's mind was lured into desiring and ultimately eating the forbidden fruit. Cain murdered his brother Abel out of jealousy which was birthed in the mind-GEN 4:3-8, Job lost all he had including his children and health so he would give up on God (a state of the mind) and curse Him, this being the sole purpose of Satan temptation or warfare against him-JOB 1:6-2:9. Jesus was tempted by Satan who attempted to expose His mind to disobey God through hunger, pride and self-will.
Therefore, how we react to temptations determine the consequences of the attack. The ability to overcome the temptations of devil and his cohorts to sin eliminates the adverse consequences of any spiritual attack according to 1JOHN 5:18 " We know that whosoever is born of God sinneth not; but he that is begotten of God keepeth himself, and that wicked one toucheth him not".

PRINCIPLES OF SPIRITUAL WARFARE
Reading EPHESIANS 6:10-18 shows that there is need to study the passage verse by verse for a clear understanding of it's message and proper application of the principles therein.

EPHESIANS 6:10 " Finally, my brethren, be strong in the Lord, and in the power of his might".
The first two requirements of spiritual warfare are for Christians to be (i) strong in the Lord and (ii) in the power of his might.
(i) To be strong in the Lord is to be spiritually well fed. In the physical, no matter how muscular a man may be, if he does not eat, he will be too weak to do anything and he may eventually die. So it is in the spiritual if a Christian does not feed on the Word of God, hence in his spiritual warfare with Satan, Jesus re-emphasised that "Man shall not live by bread alone but by every word that proceeded out of the mouth of God"-Mat 4:4. The truth that spiritual strength comes from the Word of God was revealed to Joshua which will ultimately be the secret of his successes in JOSHUA 1:7-8 "Only be thought strong and very courageous, that thou mayest observe to do according to all the law, which Moses my servant commanded thee: turn not from it to the right hand or to the left, that thou mayest prosper whithetsover thou goest. This book of the law shall not depart out of the mouth; but thou shalt meditate therein day and night, that thou mayest observe to do according to all that is written therein; for then thou shalt make the way prosperous, and then thou shalt have good success".
(ii) The power of his might is the Holy Spirit which the Christian is endowed with according to the promise of Our Lord Jesus Christ in ACTS 1:8 " But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judea, and in Samaria, and unto the uttermost part of the earth". Therefore, any Christian that wants to consistently win his spiritual battles must make the Holy Spirit a continual prayer request which is the will of God for His children as Jess pointed out in LUKE 11:11-13 " If a son shall ask bread of any of you that is a father, will he give him a stone? Or if he ask a fish, will he for a fish give him a serpent? Or if he ask an egg, will he offer him a scorpion? If ye then being evil, know how to give good gifts unto your children: how much more shall your heavenly Father give the Holy Spirit to them that ask him?

EPHESIANS 6:11 " Put on the whole armour of God, that ye may be able to stand against the wiles of the devil".

Now, we are told to "put on" which means it is our responsibility to consciously wear the whole armour of God. What then is the Armour of God we are told to put on? The armour of God is RIGHTOUSNESS! In fact the Bible reveals the combination of the Word of God, the power of God and the armour of God which is Righteousness in 2 COR 6:7 " By the word of truth, by the power of God, by the armour of righteousness on the right hand and on the left hand". This passage reveals that the armour which is righteousness is of two parts which we bear in our two hands spiritually as they serve defensive and offensive purposes. It is like a soldier who holds a sword on his right hand and bears his shield on the left hand, ready to do battle. What this means is that when we feed on the word of God and empowered by the Holy Spirit, we are able to do works of righteousness which becomes both defensive and offensive weapons in spiritual warfare. Example: forgiving people their offences is an act of righteousness that is defensive and helping such persons in their time of need is an offensive strategy of righteousness in spiritual warfare as outlined in ROMANS 8:17-21 "Recompense to no man evil for evil. Provide things honest in the sight of all men. If it be possible, as much as lieth in you, love peaceably with all men. Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord. Therefore if thine enemy hunger, feed him; if he thirst, give him drink: for in so doing though shalt heap coals of fire on his head. Be not overcome of evil, but overcome evil with good". In this passage the Bible tells us the practical way to send fire against enemies is to do good to them and not by praying down fire as is popular today which Jesus rejected in LUKE 9:51-56.

EPHESIANS 6:12 " For we wrestle not against flesh and blood, but against principalities, against powers, against rulers of darkness of this world, against spiritual wickedness in high places".

This verse invariably reveals the truth that though we may have human enemies who oppose us in wickedness, the real enemies are the evil spiritual forces who use these men in the physical realm to carry out their purpose. So, once Christians are able to defeat the evil forces their human agents are rendered powerless and are of no consequence at all. The classes of evil forces battling us in spiritual warfare are:
(i) PRINCIPALITIES: They are called Archos in the Greek text. They are next in authority to Satan and they rule over territories where they work to ensure that Satan's agenda is carried out in their domain. It is necessary to point out that God has His own principalities that also spiritually control territories for His own agenda. Scriptural revelation of both God's and Satan's principalities is in DANIEL 10:13,20-21.
(ii) POWERS: Exousias in the Greek text which means "delegated authprity" hence they serve as cabinet ministers to the principalities. They work to influence and control the political, social and economic life of man in their respective territories. In pagan or heathen societies they are the gods of agriculture, fertility, medicine, oratory, business etc. See ACTS 14:11-13; 19: 23-28.

(iii) Rulers of Darkness of this World: Kosmokraterors in the Greek text which means "harnessed raw power". These evil forces are organised by Satan as his infantry soldiers to raid and destroy every facet of man' life. They are behind witchcraft, enchantment, divination, necromancy, charm, astrology and all kinds of occultism. See ACTS 16:16; 8:9-11; 19:13-20.

(iv) Spiritual Wickedness in High Places: Pneumatika-Ponerias in Greek. These are evil spirits in heavenly realms. They work to influence and control man's spiritual life through faith in false and idolatrous religious beliefs and worship. They are therefore represented on earth using the images of the host of heaven such as the Sun, moon, stars and the planets. See 2 Kings 23:5.

EPHESIANS 6:13 " Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day and having done all, to stand".

Because we have spiritual enemies who are hell bent on warring against us, it becomes most necessary that we make use of the whole armour of God which is Righteousness applying both it's defensive and offensive strategies to make us spiritually fortified and victorious in the evil day of their attack. The evil day is actually every day as temptation to sin and be vulnerable to devil's attack can happen at any time as explained in EPHESIANS 5:14-16 "Wherefore he saith, Awake thou that sleepest, and arise from the dead, and Christ shall give thee light. See then that ye walk circumspectly, not as fools, but as wise, Redeeming the time, because the days are evil."
Having done all to stand is a military phrase which means having conquered all, stand and be ready to do battle again, just as Satan left for a season after his failed temptation against Jesus Christ. See LUKE 4:13.

EPHESIANS 6:14 "Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness"

To stand therefore is to always be ready. "Having our loins girt about with truth " is something spoken of Jerusalem Christ which is attributed to his righteousness and faithfulness during His reign in ISAIAH 11:5 " And righteousness shall be the girdle of his loins,and faithfulness the girdle of his reins". Jesus Christ himself enjoined Christians to adopt the lifestyle of righteousness and faithfulness which is illustrated as girding one's loins, because it will keep us ready for His second coming according to LUKE 12:35-36 " Let your loins be girded about and your lights be burning; And ye yourselves like unto men that wait for their lord, when he will return from the wedding; that when he cometh and knocketh, they may open unto him immediately".
The reason why Christians must always gird their loins in readiness for Christ's second coming is because it is the ultimate battle Satan wants us to lose as inferred in 1 Peter 1:13 " Wherefore gird up the loins of your mind, be sober, and hope to the end for the grace that is to be brought unto you at the revelation of Jesus Christ".

Having on the breastplate of righteousness is a spiritual defensive armour. We put this on by ensuring that the intentions of of our actions are borne out of faith in the word of God and love for man and God as outlined in 1 These 5:8 "But let us, who are of the day, be sober, putting on the breastplate of faith and love..."

EPHESIANS 6:15 "And your feet shod with the preparation of the gospel of peace"

Having been told that our enemies in spiritual warfare are the evil spiritual forces and not really their human agents, and since we cannot preach to these evil forces to repent, it is then clear that this verse is telling us of the need to preach the gospel to the human agents of evil forces as part of spiritual warfare. Christians must understand that these evil forces neither loves us nor those that serve them as their main aim is to destroy all mankind, whether Christian or not. Our Lord Jess Christ pointed this out to his disciples when they wanted to call down fire from heaven to destroy their supposed human enemies in LUKE 9:51-56.
In physical warfare "propaganda" which can be true or false is usually deployed to make both soldiers and civilians of the opposing side to surrender out of fear of an impending doom. However, for Christians the act of preaching the gospel in spiritual warfare is not really propaganda but propagating the truth of an impending eternal blessing for those who surrender to Jess Christ or eternal damnation for those who would continue to oppose Him. Hence Christians have been spiritually commissioned as Ambassadors to facilitate the reconciliation of men to God as emphasised in 2 COR 5:17-20 " Therefore if any man be in Christ, he is a new creature: old things are passed away: behold all things are become new. And all things are of God, who hath reconciled us to himself by Jesus Christ and hath given to us the ministry of reconciliation; To wit that God was in Christ, reconciling the world unto himself not imputing their trespasses unto them and hath committed unto the word of reconciliation. Now then we are ambassadors for Christ as though God did did beseech you by us: we pray you in Christ's stead, be up reconciled to God".

Christians must be careful not to be carried away by emotions of being hurt by the evil activities of men and decide to be indifferent to the salvation of such men but rather anxiously expect Hod to destroy them. This is because where such men die in their sins, it is Zgod who has lost a soul he created to the devil and He will hold Christians around such a man accountable except where the man refused to repent after he had been preached to, as outlined in EZEKIEL 33:1-11.

EPHESIANS 6:16 " Above all, taking the shield of faith, wherewith ye shall be able to quench all fiery darts of the wicked".

Above all signifies the utmost importance of using the shield of faith with which we are able to defend the fiery dart of the enemy. The Christian faith is primarily the practical belief in the salvation of souls through the sacrifice of Jesus Christ. This faith becomes a shield in spiritual warfare when the elements of this salvation which are the blood and water of Jesus to overcome the domination of Satan according to 1 John 5:4-6 " For whosoever is born of God overcome the world and this on the victory that overcome the world, even our faith. Who is he that overcome the world, but he that believe that Jesus is the son of God? This is he that that came by water and blood, even Jesus Christ; not by water only, but by water and blood. And it is the Spirit that beareth witness, because the Spirit is truth". While the blood of Jesus paid the price for our sins, His water which he also shed on the cross washes us from daily contamination of sin as we walk through this world, thereby sustaining us in faith and becoming a spiritual shield of faith against the condemnation of Satan. Jesus taught and demonstrated this in JOHN 13:5-15. This demonstration of using water to wash the feet as a cleansing from daily sin which He admonished His disciples to do for one another is clearly taught as a shield of faith against the attack of sin in Ephesians 5:25-27 " Husbands love your wives even as Christ loved the Church and have himself for it That he might sanctify and cleanse it with the washing of water by the word. That he might present it to himself a glorious church, not having spot or wrinkle or any such thing but that it should be holy and without blemish.
The fiery darts which the shield of faith defend us from are those passionate temptations or sins such as fornication as illustrated in PROV 7:7-23.

EPHESIANS 6:17 "and take the helmet of salvation and the sword of the Spirit, which is the word of God".

The helmet of salvation in spiritual warfare is the Hope of salvation as revealed in 1 Thess 5:8 "...and for an helmet, the hope of salvation". The Christians hope of salvation is the expected return of Jerusalem Christ according to 1 Thess 2: 19 " For what is our hope, or joy, or crown of rejoicing? Are not even ye in the presence of our LordJesus Christ at his coming". Once we Christians have this hope in us in all earnestness it becomes a helmet that protects us from fatal injuries even when we fall to the attacks of the devil because this hope will motivate us to be restored in faith.

The sword of the Spirit is the word of as stated in the passage. Even the devil uses this sword against the believers as can be seen in the temptations of Eve and Jesus.

EPHESIANS 6:18 " Praying always with all prayer and supplication in the Spirit and watching thereunto with all perseverance and supplication for all saints".

Praying always is an indication that spiritual warfare is an ongoing affair every day. Praying with ALL prayer shows that warfare prayers is not limited to binding and loosing or fire prayers but also includes prayers of thanksgiving, intercession, confession of sins, supplications, healing and miracles, daily provisions, speaking in tongues,etc.watching requires being sober and alert to what is happening around us in all places at all times.
Finally, and very importantly, christians must pray for each other as no war is fought by a single person.