Thanksgiving verifies capacity of soul to appreciate God. Thanking God in advance of the answer is an act of faith. Confidence for the future is based on confidence in the past. Do not forget to stir in a generous amount of thanksgiving before you get the answer. If we do not appreciate God we will not even pray properly much less give thanks.
Thanksgiving implies gratitude.
Gratitude implies submission to God. When we become convinced that God works all things together for good, we are grateful to a sovereign God. Thanksgiving indicates a heart that is at rest. We come to rest in the will of God and submit to whatever he chooses to do. Whatever the outcome we rest in God's sovereign hand.