It's a rental so buy something that you can take with you that will work in your next home. Just stay with green and white. You may not be able to change the panels, but you could add to them where it can't be seen from the outside. Add white to the outer side of the blue panels. Then get a navy and white throw pillow for the accent on the white sofa.

Thanks for posting new views of your room. You are right, nothing can go in front of the paneling, and we won't block the built-in cubby. In that case let's work with the rest of the space. I found a picture on Houzz for your gallery wall. I think this will allow you to bring in color and texture and interest to your wall without taking up space like furniture would. Try to play with portraits and a couple of paintings in there too - mix it up. Otherwise I would not put anything at the top of that landing (I'd remove that console table). That picture wall should be enough visual interest to your space and it'll draw the eye to the furthest wall as you walk in your house. I would try a small piece with closed storage between the bottom steps and that door by the entry. It looks like the space is no wider than 26", so it'll be a challenge to find something that fits and is tall enough. I would not use the wooden piece you showed above because you want wider proportions and fairly narrow depth so you don't bump into it as you walk by. (something like this ) I would hang a mirror on top of primping. By the cubby you could add a single seat stool. I'm not particularly suggesting these colors for the stool and bombe chest but something along these shapes. At this point if you do that big picture wall and add these two pieces of furniture and a mirror, you might not need to hang anything on the wall above the cubby. Also, I noticed your chandelier is quite substantial for the space and hanging pretty low. Would raising it a little or replacing it by something a little smaller be an option?

If this photo from your ideabook is the look you are going for, try adding a rug and inexpensive coffee table. To keep budget down, try an indoor outdoor rug you may find on sale at the end of the summer. The other thing you could change easily would be curtains or other window treatments in a zingy color or pattern. Perhaps there are curtains in another part of the house that could be swapped with these? Try taking them down to get a good look at the blank space possibilities.

A few simple steps can give your room a lot more vibe! Try pairing the drapes with sheer curtains, that will give the window more depth. The tv wall could be your accent wall, a dark blue would actually work very well. If the TV has backing, I would hang it on the wall, a few inches above the furniture piece. The two frames above the white dresser should go below the wall clock. Instead, a large art piece (about the length of the dresser) would complement that wall much better. I would also replace the coffee table with a rectangular, heavier glass and metal table, placed in the center. Also pillows. Pick up colors from your art work and the accent wall and use those to find pillows to decorate your sofas. Hope this inspires :-)