1.paint the walls with your fav colers
2.I would suggest you have wood floors so that when you are having a sleepover and you spill something its easier to clean up.
3. have a couch or something like that if you like that type of thing
4. have tour room the way it makes you happy
What are you into? Think about things you like or colors your like.
You could go with a princess theme and have mostly pink.
Or a more punk rock theme with band posters and stars and neon colors.
If your more into sports, have a sports theme.
It really should be about what your interested in and what you like and makes you happy.
Paint the walls black and dot them with white 'stars". Add a moon and maybe a spaceship or something...How to decorate my room without ruining it?