I think the general rule set I want to use right now is the following:
- Read a lot.
- Write a lot.
It's simple, and open. I've seen several variations of it, but most recently I read it in Stephen King's
On Writing. Of course, he has much else to offer as advice, but this, he contends, is the most crucial foundation. He quantifies it with the suggestion of writing 1,000 words per day, every day, and then getting up to 2,000 eventually.
In terms of reading and writing, he himself takes 4 to 6 hours a day, and he reads up to 80 books a year, mostly fiction. Considering the average American watches 4 hours of TV a day, I can't see how one couldn't fit somewhere near that, even if they had a day job. Even half of that is better than nothing.