I would like to know whether I should pray for something I want or whether I should just pray for God's Will to be done?
To pray for God's Will to be done is the highest form of prayer. But a beginner finds it almost possible to pray to God sincerely to fulfil him in God's own way. So when the seeker is just starting out, it is advisable for him to pray to God for whatever he feels he needs most, whether it is patience, purity, sincerity, humility, peace and so forth. Then God will give the seeker a little peace, light and bliss, which are the precursors of something infinite that is going to come into his inner being. Once the seeker has received some peace, light and bliss and they have become established to some extent in his inner being, at that time he will have some confidence in God's operation and also in his own life of aspiration.
When one is making very fast progress or is a little advanced, he feels that there 'is some reality within himself and that this reality is not going to disappoint or desert him. Then he feels that God is fully aware of what he desperately needs and is eager to supply him with those things. When a seeker feels this kind of confidence within him, that is the time for the seeker to pray, "Let Thy Will be done." At that time he can sincerely say, "God, I want to please You only in Your own way."
Prayer is best expressed in my clay-to-day life when my prayer has become a spontaneous, self-giving surrender to the Will of God.