One reader asked me about wearing sunglasses with hijab. There's no hard and fast rule about which styles work best. You need to go into a shop and try out different ones in front of a mirror. Depending on how you wear your hijab though, don't go for sunglasses with large frames, as they'll make your scarf stick away from your face and look strange! Here's a picture I found on the internet. What style are you?
And here's a collage I put together myself. Check out the blingin' hijabi in the rust-coloured coat!