I think applying olive oil on your hair is good. Also try using a conditioner other than shampoo if you haven't been doing so. Or maybe your current conditioner still not moisturising enough. Can also try using hair mask (used about once a twice a week, not for daily). Serve as DIY hair treatment to repair damaged hair, no need go salon to do. But if got money to throw, can go salon for more professional treatment

Some people also say should never go out with bare hair, must apply some 'protectant layer' such as a gel, gloss whatever to protect the hair against damaging environmental factors outdoors.