There is a strong connection between mental pictures and emotions. If you visualize something happy, you will feel happier and if you visualize something sad, you will start to feel sad. Here is one way to take advantage of this phenomenon.
Pick a goal that you want to achieve. You may want to start with a small goal and work your way up to bigger goals as you gain practice with this technique. Let’s say that your goal is to go bowling and get two strikes in a row. Close your eyes and picture yourself bowling. Try to involve all of your senses. How does the bowling alley sound? What does the ball feel like? Do you notice particular smells? Visualize yourself getting the two strikes in a row. Pay attention to your feelings and recognize how much you will enjoy achieving this goal. This visualization will help your mind prepare for achieving the goal.