ok, so this is basically an age old trick for getting wavy hair. put it in plaits and go to bed right? i used to do this all the time, but the problem is, i like to wash my hair every morning, and having it in plaits means i can't! soooo i like to do this instead.
start with relatively dry hair, prep it with heat protectant and any styling produts you like to use, like mousee or gel. personally i dont like to use these things but i do LOVE beadhead cocky which is volumising and heat protecting, so thats what ive used here before blowdrying.
section your hair from ear to ear, and clip the top half out of the way. split the bottom section in half and secure one side with something.
start plaiting th section you have left, which should be a quarter of your hair. i do quarters bcause i have thin hair, but if you have thicker hair you might want to do more sections. the bogger your sections, the looser your waves will be.
undo the braids, and losen the waves slighly with your fingers
spritz with a little bit of dry shampoo to mattify and mess it up a bit. volumising powder is better for this but is waaay more expensive than good ol' batiste!