Here's another quote I have underlined in Stephen King's On Writing:
If you want to be a writer, you must do two things above all others: read a lot and write a lot. There's no way around these two things that I'm aware of, no shortcut.
He later refers to "read a lot, write a lot" as the Great Commandment, and I agree with him that it's one all writers should follow. My favorite genre to read is paranormal fiction, and that's also what I write. Reading outside your chosen genre is important, though, and there's a fair amount of diversity on my bookshelves. Mysteries and thrillers, a smattering of literary fiction, biographies and histories, an entire bookcase full of books I refer to as the "musicology section." I use research as an excuse to slowly expand the metaphysical section. I've got my favorite authors and favorite books, both in and out of my genre. There are plenty of books that turned-down page corners and underlined passages. Sometimes I'll pull a book from the shelf and just re-read a favorite marked passage. Whether I'm looking for inspiration or a visit with an old friend, it's always nice.
The "write a lot" portion of the Great Commandment is harder. Writing every day is a huge commitment. Sometimes life gets in the way. Sometimes the voices are quiet and there's no story to tell, at least not with any great urgency. King says you should write two thousand words a day. I think that's a great goal to have, as long as I have two thousand words of something to say every day. Last year I made it to the goal line of fifty thousand words for National Novel Writing Month, but after three weeks of forced daily word counts I was churning out pure garbage. It felt like a hollow, empty accomplishment. My opinion on daily word count goals is, your mileage may vary. If you love writing, you will write a lot, but don't sweat it if you're not keeping up in the daily word count reports on Twitter. I think the main goal a writer should have is, don't let any story you want to tell slip away. Capture it, write it, make it the best you can, then capture another. Never stop writing.