Just don't pick green, because you want the features of your sofa to stand out. You don't want it to camouflage in with the room so no one can see it. Pick a color that highlights green. Orange and yellow are good examples that will work. Different shades of white are also another option. Just stay away from green, blue, brown, or any of the darker colors.

I myself have 2 hunter green sofas in my apartment. I have beige walls and I feel it accents them nicely. If your using a beigeish carpet, it will match perfectly.