Positive thinking is a practice, one that you must work with daily and apply regularly.
To have a positive thinking mindset you need to have positive thoughts. They should be in your mind constantly. The best way to get started is to change the way you think.
So, start paying close attention to what you think. If a thought is not helpful, if it does not fall in line with reaching your highest potential, if it does not make your life more enjoyable, or if the thought is going to attract what you do not want, try to change it right away.
Replace it with a thought that is better. Think of a way to put that better thought into words. Say it out loud. Sing it. Turn it into a rap verse. Do whatever you need to do to make the new, more positive thought seem 100 times more powerful than the one it replaced.
This new thought should motivate you, remind you of your talents, and give you confidence to move toward your highest potential. Put on a different thinking cap.