In the book of James we are told that often we don't get what we pray for because we are asking with wrong motives so that we can use the answers for our own purposes. I have found that one of the most rewarding aspects of prayer is to begin by asking God what or who He wants me to pray for. That might sound a little strange at first, but if you really think about it, one of the things we are trying to do when we pray is to invite God into the situations we are praying about and ask Him to intervene or work in some way. If we learn to ask God what He wants us to pray for, and He shows us, then we don't have to worry about whether we are praying according to His will or not. If He puts on my heart to pray a certain way for a particular person or situation, then I know that is what He wants to do, and I can be confident that I am praying according to His will and purposes. He is just asking we to invite Him into the situation so that He can work His plan. I have found that this can be a very powerful and rewarding way to pray.