First and foremost, even if you don’t feel like it or don’t know, trust yourself.
You are going to be able to do more than you know you’re capable of. You just have not yet been put into some of those situations.
So if it’s looking scary, easier said than done, but just jump, go start something. And it might be wrong, it might be completely the wrong thing, but the wonderful thing about doing something, even if it’s wrong is maybe it’s perfect.