Personally, I had a great education. My mum was a trained teacher, a Montessori teacher, and I know that I could not have written 'Eragon' if I had gone into a public school system because I would have just been too busy attending classes and doing homework - I wouldn't have had the time to write.
I find inspiration in many places. Sometimes music gives me the kernel of a story. Sometimes it's dissatisfaction with the plot of a movie or a book that gets me thinking. Sometimes it's love of a movie or book.
If you want to be a professional writer then you need to write consistently. Inspiration strikes about once every blue moon which, for me, is once every two and a half to three months, which is when I'll get really and truly inspired about something.
I've stood outside my house in Montana looking at the northern lights... crackling against the night sky. To me, that's magic.
I think I learned most from editing, both editing myself and having someone else edit me. It's not always easy to have someone criticize your work, your baby. But if you can swallow your ego, you can really learn from the editing.