I think making mistakes and discovering them for yourself is of great value, but to have someone else to point out your mistakes is a shortcut of the process.
I began the way nearly everybody I ever heard of - I began writing poetry. And I find that to be quite usual with writers, their trying their hand at poetry.
I used to write sonnets and various things, and moved from there into writing prose, which, incidentally, is a lot more interesting than poetry, including the rhythms of prose.
I'm crazy about Grant: his character, his nature, his science in fighting and everything else. But I don't like the idea that he never accepted the blame for anything, always found someone else to blame for any mistake that was ever made, including blaming Prentiss for Shiloh.
I think that everything you do helps you to write if you're a writer. Adversity and success both contribute largely to making you what you are. If you don't experience either one of those, you're being deprived of something.
And I'm a slow writer: five, six hundred words is a good day. That's the reason it took me 20 years to write those million and a half words of the Civil War.