I get really good curl definition by applying products to wet hair upside down and then scrunching out excess water as I go (this helps to promote clumping).
Next (and this is really key w/finer hair) w/hair still flipped over, I start diffusing upside down (High heat, Low setting). This allows curls to form more freely w/out getting crushed by gravity & the weight of hair. BTW, it also gives really great volume & lift to roots.
Once hair is about 30-40% dry, I flip upright and continue till finished. All thru the process I gently lift ends upward (sort of like pixie drying) and once cast begins to set alternate in cool setting to promote shine and calm any frizz.