Make your Dreams larger than your Doubts
Just the awareness that you are being consumed by doubts and fears about your goals is a fantastic first step.
Why? Because what you focus on is generally what you get. Whether you believe in the Law of Attraction on not, the fact remains that your brain is very good at focusing on a task and getting on with it. If that task is to worry about not being good enough to achieve something, then your brain will say “easy - I’m on to it. What would you like me to focus on next - feeling inadequate?”
So now every time the thought pops into your head that you likely to fail at something, switch the channel. Go straight to “Wouldn’t it be amazing if I achieved X. How good would that be?”
Sure, you still have to put in the effort, activity and planning to achieve said goal, however this time your chances of succeeding will go up exponentially.