Using encouragement quotes, quotes on positive thinking and other positive phrases to motivate yourself to take action is a good tool for success. Keeping these good quotes around you, however, is more important than most people would first guess.
The mind is of the flesh. Let the Spirit of God take over, and cleanse you of your errors and doubts. It's through Him we find the truth, and path of our calling. We have authority over our mind, because the Spirit gave us that power. (Law of Attraction)