It's never easy, slipping on a pair of sunnies in the shop, peering up at the mirror and trying to work out whether they make you look fab and on trend, or like a crazed bug.

This season there is nothing subtle about the sunglasses trend. They're heavily influenced by Mad Men and have a '60s twist. Bold colours and unconventional shapes take the lead, combining retro with a futuristic feel. This basically means, if you find the perfect pair, you're going to need a whole new wardrobe to match.

However, in order to choose a pair of sunglasses that will last more than just a season and ensure you're sophisticated and chic whenever the sun is shining (or you have 'morning after' eyes), here's how to choose...

First, ask yourself a couple of questions. Do they sit in line with your eyebrows? Does the shade colour look good with your hair and skin tone? Could you wear the style with a variety of different looks, and of course – what do they say about your personality?

Also, consider the following:

* If you've got a round face find glasses that add some balance. Rectangle-shaped frames will add a bit of length to your face.

* A square face sometimes needs a bit of softening up. Oval or round frames will help tone down strong features.

*If you've got an oval-shaped face you can pull off most looks, but avoid oval frames.

* To soften the chin area of a heart-shaped face, look for oval-framed sunnies.

It's pretty simple when you get the hang of it. That said, don't stick to what the rule book says, experiment and find a look that works for you and screams, "hello world, check me out"!