Your celeb-approved summer hair guide is here

What are their secrets?

OK, time for Humidity 101:

If you want perfectly-imperfect waves

Don't worry, we made a tutorial

Here are the secret ingredients for Olsen-worthy waves:

Dove Refresh+Care Invigorating Dry Shampoo, $3.99) 

If you have super-straight hair

True Detective

If you have fine hair

like this one by R + Co.

If you have curly hair

Two words: Salt spray

And finally: Prep, prep, prep