Prayer

The past few days I have been analyzing prayer. It seems that I have a difficult time "praying believing", as my skeptical side always throws in it's opinion. And then when a prayer isn't answered the way I want, I say to myself "well, what was the point in praying anyways?" The Bible has much information on prayer, and the passages indicate we are to pray "without ceasing" "confidently" "fervently" and so on. I seem to pray half heartedly and really wonder how to improve my confidence in the power of prayer (besides praying for it!). Deep down I know that God is going to do what's best for me, so why ask Him? (Because He told us to!) And doesn't He get sick of some of the repetition? (No, He doesn't). God sees the big picture, which I don't, and I do wholeheartedly trust He is going to teach me what He needs. I know that mostly the problem is the devil just trying to dissuade me, but I guess I wish I could learn how I can pray more effectively and not just let things happen as they are going to anyways. Any thoughts??