Well here's what I do. Mind you, my hair has a natural wave to it but isn't tight curls or anything.
First off, I only gently squeeze out water from my freshly washed hair, I don't rub it because that increases frizz.
Then, when my hair is somewhat dry (I don't want it soaking wet), I work in some curl creme (I use B&b Curl creme fro med/thick hair). Once you do that, I grab sections and twirl them using my fingers, this helps define curls and eliminate frizz.
After having twisted all my hair, I do the scrunching motion with my hands.
Here comes the diffuser part. I use the diffuser and try to keep the twisted still twisted. I move the diffuder from section to section of hair, and scrunch it using the diffuser itself. Basically, I just hide the hair under the diffuser and keep it near my scalp.
Finally, once it's dry enough for you I work in some anti frizz serum (I use B&b Defrizz) and spray lightly with curl enhancing spray (I use Catwalk Curl Spray).
Voila, you're done! Hope that helps!