I am reading, slowly, through Matthew Henry's book, Method for Prayer. You can read it too, for free here. He takes you through how to pray, but unlike other books on prayer that I have read, he gives you various ways to pray each step with Scripture. I find it very helpful and comforting to know I am praying God's words. It frees me up to pray freely, because I am more likely to pray for God's will then my own.
The following prayer was on my heart yesterday. May it give you peace like I received...
Lord, all our longing is before you, and our sighing is not hidden from you, even the sighs and groanings that are too deep for words; for, he who searches the heart knows what is the mind of the Spirit.
(taken from Romans 8:26-27)