While Jesus called children to him, we should not assume that we should remain childish in our prayers. As a child we will pray that God the Father will fulfill our wishes, desires and sometimes real needs. As we mature in our faith, our prayer should also mature to requests to be made anew, or to be made more Christ-like, or to be done over when we know we have had moral failure in our life.

I particularly like the beginning of the prayer of St Frances Assisi as an example of mature prayer:

O Lord, my Christ, may we have Thy mind and Thy Spirit.