Outdoor curtain panels can screen off things you don't want to look at, soften a seating area, and stop breezes. Here is a great blog on how to create them if you are crafty!
Of course, if you are not feeling the crafty angle, you can purchase a wide array of panels.
One of the most important things to think about are weights, to hold them down in the breeze. They usually have an open ended hem, where you can poke a chain through, cut into lengths at your local Home Depot store. Normal indoor weights will leave your panels blowing around. Or, you can order lengths online.