Use a clarifying shampoo at least once a month. Wavy hair tends to get build-up faster than curly hair. Build-up can weigh down your roots, cause frizz and other problems.

Only brush your hair while in the shower. Brushing your hair after showering or between washes will flatten your waves.

Wear your hair in a loose bun (this is called a "pineapple" in the CGM world) at night to preserve your waves overnight

Try diffusing your hair instead of air drying. For many with wavy hair, diffusing makes waves tighter and gives more volume

Test out wet styling and damp styling to see which results you prefer. 

Damp styled  VS Wet Styled

Use gel or mousse  and use enough to create a crunchy cast. Once it's dry, squeeze your hair to break the cast and make it soft. Casts do wonders for frizz control & wave definition!

When problem solving, try to change techniques first. Techniques make a bigger difference than products.

"Scrunch" your hair while in the shower. This will help your waves spring up and will help hydrate your hair. 

Try a sulfate-free shampoo instead of a cowash.  For most people with wavy hair, cowashing is too heavy and will flatten roots.