I think you picked beautiful colors for your walls. I would suggest some art that plays with the neutrals in the room (beige, sand, cream) and picks up some of the blue in the rug if possible.

Also, I hope it's ok to say this: I think the bookshelf doesn't match the elegance of the rest of the furniture. If it is possible to take it out of the room, I would suggest putting it elsewhere (it's a nice piece, just doesn't seem to fit with the rest.)