There's nothing quite as tricky as trying to buy sunglasses or opticals. There's the classics - aviators and club masters, wayfarers and cat eyes but where do you go from there? Do you opt in for a flash mirror lens? Or perhaps a matte frame? And that's without even touching on the minefield that is face shape. That's why we're got our comprehensive guide on picking the right specs for Summer.  Back to basics - Face ShapeThe easiest way to decide what glasses to go for is to determine your face shape. This can be a bit tricky, but studying your face outline and looking at widths are a great jumping off point. Face shapes are most likely to fall in to one of four categories - round, oval, heart or square. Heart shaped:christinaIf you've got a heart shaped face you tend to have a wide forehead and a narrow chin and more than likely quite high cheekbones. A good pair of cat eyes is perfect for this face shape, balancing everything out.Miu-Miu-MU-04PS-7S09S1-hd-1NWMiu Miu Dior-Audacieuse-1-4BTY1-hd-1NWDior Oval Shaped:beyonceIf you're lucky enough to have an oval shaped face you can pretty much have your pick of the proverbial litter. You have a balanced forehead with a narrow chin and forehead as your defining features. Any pair of sunnies on this list would look great on you. Take full advantage of this and experiment with different shapes.marc_jacobs_mj_472s_l84_y1_1392Marc Jacobs Linda-Farrow-Luxe--LFL289-C2-hd-2NWLinda FarrowRound faced:kirstenIf your face is made of soft curves with few angles with an equal width and length you have a round face. If you've got this face shape you're going to want to avoid round sunglasses like the plague. Instead opt for square or angular frames to break up your look.Oliver-Peoples-NDG-1-OV5031S-1205R9-hd-1NWOliver Peoples Prada-PR28PS-1AB0A7-hd-1NWPrada Square faced:angelinaOur final face shape is defined by a defined jaw and a more squared off chin and forehead. Like with a round face you're wanting to go for contrasting shapes, this time breaking up the angles with some round frames.Fendi-FF0026S-7QR-OU-hd-1NWFendi Chanel-5279-1295S5-hd-1NWChanel Sizing them upGlasses size vary vastly from brand to brand and often it depends on what kind of look and lens you're looking for. If you're a glasses wearer already you can usually find out your size on the inside of your specs. If you're still worried about this guy - pop on to Pret Chat where Alison will be more than happy to advise you on finding the best frame.Top of the trendsWe've seen glasses become a popular fashion accessory year round. It really has come an anything goes attitude but pick our favourites from the big players at the moment.Flash mirrorVictoria-Beckham-Feather-Aviator-VBS2-C06-hd-1NWPerfect for those looking to make a statement, flash mirrors have been growing in popularity. These brightly coloured specs sure pack a punch and come in a variety of tints from rose gold to bright green.Summer BrightsColour is a bit hit this Summer so it's perfect if you're looking for something with a bit of personality, while keeping with more classic contemporary shapes. We love that brands like Ray ban and Sherbet are experimenting more with colour and texture while keeping with the shapes we know and love.Sherbert-Strawberry-and-Lemon-hd-1NWVintage ClassicNeutral colours and shapes reminiscent of bygone era's are what really shape this trend up. Oliver Peoples really leads the pack with this one with close competition from Cutler & Gross and Persol. Perfect if looking for something timeless with real character.Cutler-and-Gross-1008-Cinnamon-Brown-hd-1NW But most importantly.....Look at what you've liked in the past and what you like on others. Eyewear is extremely personal and can completely change the way you look and feel about yourself. No matter what frames you choose, make sure that you're UV protected and that they are a pair you totally love!