It's very rare when I don't see Kylie Jenner, from E!'s Keeping Up with the Kardashians, without her hair stuck to her face. She already has a short and round face and by constantly having her hair covering her ears and cheeks she makes her face look even more squashed looking.
Keep your hair up in a pony tail or bun, or clipped back to make your face look longer and slimmer.
To make your long face look shorter have your hair tucked behind ears or flipped to the side, also try keeping in like Kylie's up there.