What can i do to keep my ps3 in good shape?

Don't drop it, hit anything with it, drop anything on it, or anything like that, no physical damage. If it's not meant to do something, don't do it. Don't leave it on very long unless you are playing it, to prevent overheating, then you will want to give it a break after the session. Also don't get liquids or dirt in it or take it apart, because that will void your warranty (if there is any on the PS3, I just know there is on the Xbox 360).