First, one considers the colors at hand. You have a brown color and a green color. Colors that go good with this are warm colors. Such as brown and certain shade of orange. Stay away from cool colors such as blue or yellow.

My suggestion would be a creamy white color – it'd keep the room airy and looking fairly big – as well as complimenting your furniture and flooring. If you wanted to make it more colorful try using some stencils and paint the shapes the same colors as your furniture and flooring to match it all in.