Increase your physical strength. Go to a gym 3 times per week and follow a specific weightlifting program.
Learn a martial art or some other self-defense system. I recommend Brazilian Jiu-Jitsu.
Learn more about a subject that intimidates you. We fear what we don’t understand.
Write down every positive thing you have accomplished in your life. It’s easy to forget.
Learn to meditate and be present in the moment.
Take account of all the good things in your life and remember the things that have worked out for you in the past, especially the things that came unexpectedly. Be thankful for all of these things and expect more of the same in the future.
Associate with people who love and support you, and limit contact with people who tend to bring you down (whether they mean to or not).
Write down everything that has been bothering you lately. It helps to just get it off your chest. Think about what changes you can make in your life (and in your thinking).
Make sure you are getting lots of sleep, consistently. It’s surprising how even an extra hour of sleep per night can make a huge difference in how we think and feel.
Find a job where you feel like you are respected and can make a positive contribution to an important cause. In other words, find what best suits you, don’t just think about the money.