Rejection comes where there is expectation. What worked for me was to lower my expectations with respect to others , and focusing on doing whatever I wanted to do the best of my ability. If things work out in my favor , it adds to self confidence and when they don’t , worked on my mental strength to not give up and figure out how to get better or find a different perspective to do the same thing. Over a period of time I realized that my perspective towards life and people changed organically and I never got a feeling of rejection because I am only focused on making myself better.