Rule of thumb for clothes, if you hav'nt worn it in a year, get rid of it.
As for stuff...I'd apply the same theory. If it has just been sitting in your house and you hav'nt used it for a year or more, sell it, give it to good will, whatever!
I highly suggest Ikea for more a compact living style. They have some great furniture/storage solutions for small spaces. 🙂
Good luck! 🙂