One of the best pieces of advice I've ever been given is that if you want to write well, you need to read - and you need to read good writing. Reading will show you what works and what doesn't in trying to tell a story. Reading will show you how good writers work their magic tricks. And reading outside your chosen genre will give you new information and new perspectives that you can bring into your own efforts. (The classic advice is "Write what you know." In practice, that's often backwards: it should be "Learn what you plan to write." Same coin, other side.)
Reading good books in helpful in a variety of ways, but lately I've found that it isn't always as helpful as reading badly written books. Yes, reading good books (and looking at how they're written) can help you hone your technique... but reading a good book always leaves me feeling satisfied, content, and settled. It's good to see how another author did something, but it's something that's done. Reading bad books, on the other hand... it kind of pisses me off. It makes me want to write things that are better than what I've just been reading. It's downright motivational.