I could give a laundry list of ways to help establish credibility.
But before numerous measures are taken to establish credibility, first and foremost, step 1, the first brick, the launch pad, we must...must be passionate about the vehicle in which we intend to establish credibility.
If we are not passionate about what we do, our business, etc., we might as well hang a sign up, "I am not passionate about what I do. I do not believe in what I do. So you should not believe in what I do."
Do what you love and love what you do. No more, no less. The rest will come in time.
Choose to be of service to others, find your purpose and make a difference.