Every failure is a lesson that brings you closer to success.
The task of the writer is to confront the chaos of existence and to find some kind of order within it.
When you have some success, the feeling of being an imposter can be real. Who am I fooling? But when you create things that only you — with your unique talents and experience — can do, then you are absolutely not an imposter. You are the ordained. It is your duty to work on things that only you can do.