How should I decorate my room?

Hi . I am about to go into the 8th grade and i have this plane white room and bed. Since its close to the summer I would have time on my hands to do a remodel of my room. I like the idea of a blue room. A bright blue room, Or a Bright green room. I just don't know what to do as bedding and lamps , desks, and all that AND WHICH COLOR TO PICK!.I don't like the color pink . But any ideas on places that are not to expensive were i can but supplies.I also like zebra and paint splatter. But what sucks is that i am going to have to share this room with my brother so nothing to girly