If people are going to hire you as their coach, then they need to trust you. They need to feel like you are a true authority on the topic they are interested in.
Depending on how you view your authority and reach in the market right now, you may or may not need to do a little bit of work. I don’t think it will take a long time to get to the point where you need to be – a lot of this has to do with perception (how others perceive you as a coach as well as how you perceive yourself). You have to be strategic about building your integrity as a coach.
You should know your subject well. You don’t want to pretend anything as a coach. You want to actually be able to help people – not just take their money. If you’re just taking their money and you don’t know your stuff, then you’re not doing your job and what you are doing might be fraudulent. I’m not saying you’d ever do that, but it’s time to make sure.