There are many types of hairstyles out there but not all of them will look good on you unless your hairstyle fits the shape of your face. Anna Lynn C. Sibal, writing on glam.com, details which haircut is most flattering for each face type.
The oval face is considered the perfect face. Almost any hairstyle will go with it, whether it's long or short, straight or curly. If you have an oval face, you will do well with having layers near your chin or cheekbones to draw attention to them. However, try to avoid hairstyles that add volumes to the top of your head because it will make your face look longer. (Famous Oval Faces: Taylor Swift, Hilary Duff, Carrie Underwood)
If you have a long or oblong face, you create the illusion of width to balance it out. You can add width to your face by doing your hair with long, side-swept bangs or chin-length bobs. You will also do well with curls and waves that frame the face. You should also avoid letting your hair grow extremely long or having your hair cut extremely short. Such extreme hairstyles will take the width from your face and emphasize its length. (Famous oblong Faces: Ashley Greene, Hilary Swank, Terri Hatcher)
People with round faces need to take some of the width and bulk off by adding length. To create the illusion of length, you can have your hair cut just below your chin or in graduated layers. Do not do your hair in short, one-length, blunt cuts as this will only draw attention to the roundness of your face. (Famous Round Faces: Emma Stone, Kate Bosworth, Fergie, Renee Zellweger)
The hairstyle trick with having a square face is drawing attention away from the jawline. This is done by putting texture into your hair. Short curls do exactly this, as well as long layers that start just below the jawline. Also, you should try not to have your hair cut in one-length bobs or wear bangs that are cut bluntly as this will only emphasize the squareness of your face. (Famous Square Faces: Keira Knightley, Rachel McAdams, Megan Fox)
You should think about bringing attention to your eyes by wearing side-swept bangs, a fringe on your brow or long layers on top. Or, you could let your hair grow and have it done in layers that gently touch your cheekbones. (Famous Heart-Shaped Faces: Zoe Saldana, Reese Witherspoon, Jessica Biel)