1) For a square shaped face
You can choose to either soften your angles or highlight as both will do you well. A wider around the cheekbone structure will help balance the angles if you wish to still pursue an angular look and given the angles, a soft frame would also suit you. This means that you can opt for slightly oval but horizontally, rectangular, circular would go well with your face.
2) For a round face
You need to sharpen your look. Rectangular frames are perfect for your look. They will dramatically alter the appearance. Guys with the really round faces should opt for nerdy frames instead of half or full rimmed. The rim will provide a more angular support.
3) For the oval face structure
You purpose will be to bring about a balance. In this case you cannot go for the basic geometric frames. The perfect pair for you will be the frames that have a rigid upper body of the rim and a softer lower body. These frames will bring out the best look in you and take away the limelight from your long face structure. Apart from these, you may carry off many frames but these will compliment your face structure the most!
|Square||Wide||Wide||Wide||Angular||To soften or highlight the angular look|
|Oval / Oblong||Wide||Average Width||Wide||Soft||To sharpen|
|Heart / Diamond / Triangle||Narrow||Wide||Narrow||Angular||To soften|