Some people wear sunglass to protect their vision from glare and from harm of the ultraviolet rays emitted by the sun; while some do it to make them look good and enhance their appeal; and others to cover their defective eyes or some unwanted marks around their eyes.
However, in choosing the right frame for your sunglass, it has to counter complement to the shape of your face. The rule to observe is that the shape of your sunglass frame should be in contrast to the shape of your face.
If you happen to have a round face made up of soft curves, you will look best in angular or square frame. And if you have a face resembling a rectangular or square shape where you have an angular face pick the round frame style.
If you have a heart shape face, try something delicate, like a wire or rimless frame style to balance the narrowness of the chin. If you have an oval face, try different frame shapes, since the shape of your face practically suits to different shapes of sunglass frames.
The secret of looking good with sunglass is contrast, because it creates emphasis and distinction to balance your features. Frames should generally be no wider than your face and with the glass setting at center not below to the eye level.
There are also frames that will make a long nose shorter, take the one with a low set bridge. For a round face to look thinner, use an angular or square shape frames.