Nada Allam 
I am someone who loves change, and tends to play around with my hair a lot. I usually part my hair from the right side, just because I am used to it. I wonder a lot, what if I part my hair down the middle, or flip it to the left side, would it match well with the structure of my face. After quite a few trials and many many errors I realized that the way you part your hair depends a lot on the shape of your face. So, here's a guide to help you decide how to part your hair according to your face shape.
1. Oval Face:
If you have an oval shaped face, that probably means you have a long and narrow face, and you don't want to elongate it even more. Side parts will be the perfect choice for you, giving the illusion that your face is wider. It has been said that the oval shaped face, is the shape that works with any type of hair sectioning. Sarah Jessica Parker is your perfect oval shaped candidate, so skim through her pictures for inspiration.
2. Square Face:
Having a square shaped face means you have a wide jaw line with sharp angles. You have two options with the square face. Either part down the center, it will frame your face and define your cheekbones. Or, you can opt for a deep side part, that way you will hide one side of the sharp angles achieving better facial balance.
3. Heart Face:
This type of facial structure means you have full cheeks and a wide forehead. The trick with this face shape is to go for an off-center part. This will cover up your forehead a bit, and make you face look thinner which will balance out all your features.
4. Round Face:
The trick to round faces is to show off your good side and elongate your face. First start by picking your good side and go for a deep side part on the opposite side. The beauty of a round face, means you can also go for a center part. This will frame your face and define your cheekbones. Look at Mila Kunis's pictures below to get a better idea.
Tip: Remember to part your hair when it is wet, so it can dry accordingly. Also when going for a deep part, make sure to part from the arch of your eyebrow.
I added a few pictures of celebrities and how they sectioned their hair, so you can get a better understanding of your face shape and where exactly to part it. Hope they help...
