Well. I know, it's not 2012 yet, but it's an essential point for me, to throw out anything I don't need anymore. I was just looking for a nice notebook to gothify, and I've found lots of stuff.
What I keep, really affects my state of mind, so I decided, to keep the happy memories, and just trow away anything else. I am sorting things in three piles:
1. Don't need it anymore: litter bag.
2. I'll use it: put back where it was.
3. It's a memory: put in a nice box, write on: stuff from the past, then put it away.
I recommend it, because you are not only make more space in your room/house, but decide, wich parts of life are not important for you anymore. I am not going to throw away everything from my past. Sometimes I look inside the "memory" boxes and throw away things.
The main thing about it, that I fell a bit purer.
So, at first I clean my room, then my mind, and my body will follow it.