While there's a decorator inside all of us, most of us would need help, help, help when it comes to actually putting together a room that's "together." Thinking of a cohesive color scheme is something that's particularly troublesome (I speak for myself, at least). One super cute idea is to let someone else do the work for you...and no, I don't mean hire a professional.
A great way to get inspiration for a room (or any project) is to look in places where you already have a great, coordinated color palette that you know you love. Eye shadow palettes will do just this trick. Find a color combo that you think is to die for, and then do your room accordingly.
Take the compact in your hot little hand, and run to the fabric store, Pier 1 Imports, the craft store, etc. and get things for your room in the colors that are in your shadow palette. Voila! You're a professional interior designer!
Pretty Little World's favorite: The shadow below (Teal Cake) from Pop! Eye Cake Shadows (this and more colors available at Sephora.com).