I hardly consider myself worthy to give advice, but I would like to expound on something that has worked for me. Character analysis.
That's right. Character sketches. Not just piddly little profiles though. I'm talking extensive stuff. This is a person that you're trying to create. A person that is making up the contents of your novel. There is always more to discover. Always more to uncover.
I get writer's block. I know, surprise, surprise. Probably one of the most obvious statements a writer can make. There are very few things I can do to break that inspiration stopping wall. One of them, the one that seems to work the most for me, is character analysis. Discovering more. It's amazing how learning one little morsel of information on one little side character, can open up a whole slew of new plot ideas.
Not only can you find a ton of character sketch material online, (I'm now going to shamelessly advertise) such as Beautiful People, but you can find some great books on the subject as well. I myself have only had the chance to get my hands on one, but there are at least a few more out there. The one I've used a little bit is called, What Would Your Characters Do. The Director recommends one called 45 Master Characters.
Check these books out. Look around for more like them. Get them from the library if you can. Find the one that works best for you. Find several that work best for you. Maybe none of them will work for you. Maybe you feel you don't need extensive character sketches. That's cool too, just remember that with writing, it's always a good idea to try something before saying it's not for you. You never know, you might surprise yourself.