Pray a little each day in a childlike way for the Spirit of prayer. If you feel that you know, as yet, very little concerning the deep things of prayer and what prayer really is, then pray for the Spirit of prayer. There is nothing He would rather do than unveil to you the grace of prayer.
God alone fully understands what each one of us needs; we make mistakes continually and pray for things which would be harmful to us if we received them. Afterwards we see our mistakes and realize that God is good and wise in not giving us these things, even though we plead ever so earnestly for them.