Flat hair on top can be caused by several factors.
Excess oil, product buildup, or simply needing a refresh can all contribute to a lack of volume on top of your head.
To combat this, try using a volumizing shampoo to give your hair a boost.
Additionally, changing your blow-drying technique can make a big difference. Try blow drying upside down to help lift your hair from the roots.
For an instant fix, try sprinkling in some dry shampoo to absorb excess oil and add volume to your locks.