SO YOU THINK YOU CAN DECORATE?

We got ourselves a new couch last week, but we're not sure if the wall color is right, the color of the couch is a very light tan and the walls are just a few shades darker...we are thinking of an olive green or something in that color family...do you have any ideas??? Brian and I are going to try and get it done this weekend and we'll post after-pictures. Would love to hear your opinion ...