Draw The Circle by Mark Batterson is a great prayer devotional. The devotional really challenged me in praying. The book also encouraged me in my faith by retelling other stories of strong faith that started from a prayer. The book really showed me the importance of praying and how much it can help others and you.
This is a great book for devotions. We do it together every morning before school. It has a lot of stories and ways to pray and ways to honor God. There was one way that he said to pray, and it was to thank God for things that God wants to happen like it's already happened. I think you'll like this book.