How can I get the most out of my MacBook Pro?

I'm just wondering if there are any small tips or tricks that I should know to keep my computer as healthy as possible. Also, what I can do to get rid of any unneeded things that take space on my computer, etc. I got my first MacBook when I was 15 and I really didn't take great care of it, and now that I'm on my second MB I want to be more responsible and make sure I'm doing everything I can to keep it running smoothly! Thanks!