Many Christians turn to God in prayer about their problems and anxieties, certain that he loves and cares for them. Some, however, experience frustration as they wait for their prayers to be answered. Do you feel that your prayers are ineffective? Does God listen when you pray?
Even if our prayers seem to go unanswered, this does not mean that God did not hear them.The Bible assures us at 1 Peter 3:12 that "For the eyes of Jehovah are on the righteous, and his ears listen to their supplication,but the face of Jehovah is against those doing bad things.” So Jehovah God hears the prayers of righteous ones, whether they are spoken audibly or uttered in the heart.
However, prayers must meet certain requirements if they are to be acceptable to God. First, they must be directed exclusively to God​—not to Jesus, to a “saint,” or to an idol. Prayers must also be offered in the name of God’s Son, Jesus Christ as stated in John 14:6.
Prayers must be offered in faith. Hebrews 11:6 says "Moreover, without faith it is impossible to please God well, for whoever approaches God must believe that he is and that he becomes the rewarder of those earnestly seeking him." Faith produces actions, and they, in turn, show that we love God and are trying to please him.
Worshipers of God must also be persistent when praying. Luke 11:9,10 says " So I say to you, keep on asking, and it will be given you; keep on seeking, and you will find; keep on knocking, and it will be opened to you. 10 For everyone asking receives, and everyone seeking finds, and to everyone knocking, it will be opened." After all, if a person prays just once about a matter, does this not indicate that he or she is not really serious about the request?
When all these had been done, we can be sure that our prayers will be heard by God and he will answer in a way we do not expect and in his own time.

gideonjeta:
Many Christians turn to God in prayer about their problems and anxieties, certain that he loves and cares for them. Some, however, experience frustration as they wait for their prayers to be answered. Do you feel that your prayers are ineffective? Does God listen when you pray?
Even if our prayers seem to go unanswered, this does not mean that God did not hear them.The Bible assures us at 1 Peter 3:12 that "For the eyes of Jehovah are on the righteous, and his ears listen to their supplication,but the face of Jehovah is against those doing bad things.” So Jehovah God hears the prayers of righteous ones, whether they are spoken audibly or uttered in the heart.
However, prayers must meet certain requirements if they are to be acceptable to God. First, they must be directed exclusively to God​—not to Jesus, to a “saint,” or to an idol. Prayers must also be offered in the name of God’s Son, Jesus Christ as stated in John 14:6.
Prayers must be offered in faith. Hebrews 11:6 says "Moreover, without faith it is impossible to please God well, for whoever approaches God must believe that he is and that he becomes the rewarder of those earnestly seeking him." Faith produces actions, and they, in turn, show that we love God and are trying to please him..

According to God, He does not answer prayers said as the hypocrites do..

5 “When you pray, don’t be like the hypocrites. They love to stand in the synagogues and on the street corners and pray loudly. They want people to see them. The truth is, that’s all the reward they will get.
6 But when you pray, you should go into your room and close the door. Then pray to your Father. He is there in that private place. He can see what is done in private, and he will reward you.
7 “And when you pray, don’t be like the people who don’t know God. They say the same things again and again. They think that if they say it enough, their god will hear them.
8 Don’t be like them. Your Father knows what you need before you ask him.
9 So this is how you should pray: ‘Our Father in heaven, we pray that your name will always be kept holy.
10 We pray that your kingdom will come— that what you want will be done here on earth, the same as in heaven.
11 Give us the food we need for today.
12 Forgive our sins, just as we have forgiven those who did wrong to us.
13 Don’t let us be tempted, but save us from the Evil One.’
14 Yes, if you forgive others for the wrongs they do to you, then your Father in heaven will also forgive your wrongs.
15 But if you don’t forgive others, then your Father in heaven will not forgive the wrongs you do. - Matthew 6 vs 5 - 15

Any prayer that violates God's commandment is a prayer God does not answer.