Xtava Black Orchid Hair Diffuser
Managing curly hair is a whole 'nother level above what straight-haired people have to deal with. (A biased statement, maybe, but I hold to it.) There are entire post-shower routines people have developed with specific instructions for applying product, drying, etc.
On the drying end of things, unless you're going to let your curls air-dry every single time — which can literally take hours — you need a good diffuser attachment for your hair dryer because it holds the curls in place as they dry to encourage curl definition, rather than blowing them all around and turning them into Frizz City.
The Xtava Black Orchid diffuser is great because it's not just a weird platform with little air nubs like most of the ones you find; it's more like a big bowl that you can actually fit your hair into — which, as anyone with huge hair can tell you, is awesome.
The one drawback is that it doesn't fit all hair dryers, only those with 1.8" diameters. Some Amazon customers have compiled a Q&A thread with some dryers they've gotten it to work with.
The Xtava Black Orchid is $13 on Amazon.