I personally don't. I have my own life and if I trained, I'd never make the time to create what I want to. In order to finish, I simply write and draw what matters to me. I look at both my fan and professional works as serious. Sometimes that means I make mistakes, but I continuously edit my drafts until they look good. I also share my pictures and take both positive and negative feedback. I once was very defensive over my works, but now I am less defensive than I used to be.
Like anyone should be, I still filter the advice I get and ultimately go off what I value. This ultimately leads me to a lot of finished products and from there I build and continue to get better and better. Sometimes, the best teacher is experience. Get as much of it as possible if you truly want to be proficient. Realize you won't always win and use that to become a stronger writer.
Worst come to worst you get some negative reviews but all that means is you need to learn from those mistakes in the next product. Some people overthink about what they should do and never get anything done.