How can I change my bedroom subtly to make a big difference?

cocobara - Nice to have a room that works isn't it? How about either putting the posters into frames, or changing out the frames? All done in the same style/color to really make a statement with them. Try adding lights to showcase these, as well - maybe track lighting or clamp lamps placed strategically in that area. Really add drama using either paint or material behind your posters or at the head board area. A bit of punch - and remember, there are a lot of "materials" out there that can me put on the wall that could add a unique feature in your room. Go to your neighborhood hardware store and just look around! Have fun and good luck. LT