The problem with the good advice is it's mostly much too simple. Joe Straczinski told me about the time that he, when young, got hold of Harlan Ellison's phone number and phoned him up. He explained that he was a young writer and nobody would publish him. According to Joe, Harlan said "They won't publish you because you're writing crap. Stop writing crap and they'll publish you." Which was very good advice, and Joe took it. But it's sort of simple.
permalink source: Neil GaimanI will function as a whetstone, which can make steel sharp, though itself not capable of cutting.
permalink source: Horace, Art of Poetry, 304-305