From How Can God Answer Prayer:

Hence prayer is usually divided into the following component parts: Adoration, Thanksgiving, Confession and Petition. This suggest a splendid order for the express of what is doubtless in the mind of every one as he comes to God, though there can be nothing stereotyped in so vital a matter. Some of the most effective prayers in the Bible are simple, earnest cries for mercy; but the Bible abounds with prayers in which something of the order noted is observed.