Artsy/beachy/surfer mature yet fun and cool bedroom?

How would I make my room look more surfer/artsy? I'm really into the beach and surfing thing and I absolutly LOVE are and music (I play acoustic guitar) and as of right now I just have my bed (of course) and a Cherry Wood bookshelf. What can I do to give it more of an artsy feel but seriously keep the surfer/beach thing in it? I'd also like for it to look mature, but not so mature to the point where you can't just chill and have fun in it (I mean play video games, watch TV, rock out to music, etc.) It's not a HUGE room, but it's not SUPER TINY either. It's a decent size. I don't really want a whole lot of furniture in it considering I already have my bed and bookshelf which take up about maybe 30% to 45% of my room space, so I'm trying to keep it simple, yet cool. I'm also planning on framing all my posters and pictures and paintings and putting them on the walls which I'm going to paint a light, tannish brown color.