Jimmy Davis has a wonderful article on prayer:
Prayer (or any other spiritual discipline such as Bible reading, fasting, silence, or solitude) is not something we do to make God happy with us. No, the spiritual disciplines are meant to make space for us to hear how happy God is with us because of Jesus. When I pray to get God to love me I am a legalist who works for God to earn the favor of God. Gospel-praying means listening to God say that I already have His favor through Christ and that I can now work with God in the resurrection power His Spirit supplies.
Read the rest of the article here: The Cruciform Life