Please, I need help from my able Nairalanders on the possible ways/ methods that will help me improve my oral English. I am a graduate but my spoken English is fairly good and I want to become extremely fluent when speaking English.
Thanks in advance.

Gud day friend,quiet understand your plight..My humble advice is read..Read..Read..Read anything you can lay your hands on...Read beyond what u normally read both good and bad writings try soughting out the difference.
Don't be ashame to ask questions where your lost.
Visit forums participate in discusion or rather read the post of others,make your observations
Lastly,buy a small,notebook in keeping records of new words and there meanings.
Digest the afforementioned..More tip later!
Shallom!

Great, thank you so much I really appreciate your advice/contribution.

I would advise you watch a couple of decent orators on film and shadow everything you hear to work on your diction. The remains of the day & The grand Budapest hotel are a good stat. Books are good, very good, but if you cannot speak properly then whats the point of knowing all those big words?

Great! I am grateful will try it and hope it will work for me.