You could call it a beautiful optical illusion.
Every woman looks magnificent in the right hat. Following are some tips to help you create a balances between your face shape and the hat.

OVAL: Lucky you! You can wear any style you choose. Pay particular attention to hats with streamlined shapes that are worn forward. In addition, square or round crowns, or brims swept up on the side(s) or back will complement you.

ROUND: Big hats are a good style for you. Try hats with wide crowns, such as a rounded mad hatter, a wide sailor brim or a wide Breton style (upturned brim). Berets, cloches and pillbox hats worn off your face can also be good choices.
Asymmetrical brims will lessen the roundness of your face. Round faces are good hat faces and look good in many styles.

LONG: Choose hats with a shallow crown or a mad hatter style with a sailor brim. Upturned brims pulled low will add width.

SQUARE: Try fedora styles, peek-a-boo brims or a sailor brims. Also, consider a beret style.

WIDE: Off the face styles, Bretons (upturned brims) or pillboxes worn back will add "lift".

HEART: Experiment with asymmetrical designs, square or round crowns tilted to one side, profile hats and brims with soft curves.

Remember, these are only tips! If you like a hat style, wear it with confidence and be happy.