The Glitch: Low Volume
Heat and moisture can cause fine hair to fall flat when temperatures rise.
The Fix: Apply a body-boosting mousse and blow-dry the hair upside-down to volumize the root. Seal in volume and seal out humidity with a dry finish hairspray.
The Products: Charles Worthington London Smart Fixx Mega Volumising Foam, $10; Mop C-System Firm Finish Strong Hold Hair Spray, $22.