I like sunglasses which look dramatic. Those with different colors and huge frames are fashionable and attractive. As the summer coming soon, it's about time to get some shades. The trend of 2013 will be unpredictable. But famous sunglasses designers have already give us tips, check this out:
http://www.redhotsunglasses.co.uk/blog/2013/02/sunglasses-trends-2013/
Something more about the trend of sunglasses in 2013:
http://www.babble.com/home/10-spring-sunglasses-trends-2013/
Personally, I think sunglasses with combined colors will be a fashion, such as white go with black. One important thing is that finding suitable sunglasses for the shape of your face is more important.