One universal law that operates for our mind is the Law of Attraction.
The law says what thought you hold dominantly in your mind will be manifested as reality.
If you entertain negative thoughts, you get negative things. Likewise, immerse yourself in positive and empowering thoughts and you get positive things in your life.
It works on the principle of like attracts like. Hypnotherapy is one way to help people build up positive thoughts so as to get more of the like thoughts.