Everyone kind of does their own thing really. A general rule of thumb is to keep things clean looking, but even that isn't something everyone does *shamefully looks at my bookcase*.
I would think about yourself and what kind of vibe you want in your room. I used to cam in front of my bookcases because I like reading and wanted to have a book-nerd vibe going on. It was messy looking though, and in hindsight I think it kind of detracted from things because there was just too much stuff to look at. Right now I cam from my bed with a bare wall behind me. It's extremely simple, but it works for the site I'm on (SM) since I'm not there to entertain like on MFC like I used to.
Some people hang up paddles and riding crops on the wall, or have a shelf with their toys. A lot of people have lights or tapestries. Some people will use blank wall space to put up decorations and things related some theme or goal that month. In my opinion the simpler the better so the main focus stays on you. Not boring by any means; interesting stuff in the background can make for good conversation starters, just don't have so much going on that you get lost in the mix. At least those are the kinds of rooms I like looking at. Check out other rooms for ideas, but don't get too hung up on it. It can always be changed.