Rectangle-shaped glasses usually work the best for round faces. Try to go for frames that are wide or thick, as they help broaden up the features and add the necessary definition to your face. Learn more at http://lifestyle.iloveindia.com/lounge/how-to-choose-the-right-glasses-for-4963.html
To choose the glasses frame, you must know that never get the same shape glasses as your face shape. If you have a round face, you can't get the round frame. Rectangle or square will suit your face shape best. You can try them on to find the best that look good on you.