Maybe you already own a dryer you like. In that case you do not need a new one, you need the right attachment. This is the lowest-effort upgrade I know, because it takes thirty seconds to fit and changes how the whole blow-dry feels.

Dyson's Supersonic r diffuser is made for the Supersonic r dryer, so if you already own that one, it is the clear match. T3's Afar diffuser is sold for the T3 Afar dryer only, so check which dryer you have before you order. Bio Ionic's Universal Styling Diffuser is named universal, which tells you it is designed to go on a range of dryers. Drybar's The Bouncer is the playful one, and Drybar is worth knowing about: the blowout salon chain was co-founded by Alli Webb with her brother Michael Landau. The Bouncer is designed for Drybar's own dryers, and the brand says it fits most other blow-dryers too.

There are two ways I use any of these. Hover diffusing means holding the dryer away from the hair and slowly moving it around the head, and it is the simplest technique to start with. Pixie diffusing uses the bowl to scrunch the hair, which is better for when you want more definition and have patience. Whatever you pick, fit it snugly and check that it does not wobble when you tilt your head, because a loose attachment ends up dangling strands around the bowl. Try hovering first. It is forgiving, it is quiet, and your curls stay where you put them.

The air is only half of it. What you put on wet hair decides whether your curls dry into something defined or something soft and loose. I apply a cream or mousse to soaking hair, scrunch upward, and only then reach for the dryer.

Fenty Beauty's Homecurl is a curl-defining styling cream, and it is the one I would start with if you want clear shape. Moroccanoil's Curl Defining Cream with argan oil sits beside it as another option for defining curls. Olaplex's No. 6 Bond Smoother is a frizz control styling cream, more of a smoothing option. JVN's Complete Hydrating air dry styling cream suits hair that likes to be left alone, and OUAI's curl styling cream carries the North Bondi fragrance, which I find clean and light.

Crown Affair's Texturizing Air Dry Mousse is the airy one, and I like it for fine hair that cream flattens.

What I would skip: turning the heat up because hair is still wet at the roots. Wet roots are normal, and the answer is another few minutes on low, not a hotter setting. I would also skip raking the diffuser through your hair like a brush. Cup the curls in the bowl, hold, then move on to the next section.

A small test for how much product to use: your hands should feel damp and slightly slippery after you scrunch, not sticky. If they feel tacky, you used too much, and the curls will dry stiff. Next time, halve it, and add a little more only to the ends if they still look thirsty.

My routine is short. Product on wet hair, scrunch, then the dryer on low heat and low speed, section by section, hovering first and cupping once the curls have set a little. Stop before the hair is fully dry and let the rest finish in the air.

Do not touch it while it is drying. Touching is what makes curls puff out. Once it feels completely dry, use your fingers, not a brush, to loosen the top. If the ends feel rough or the scalp feels hot, turn the heat down or stop early, and use a heat protectant when you can. Hair varies a lot, so give any new tool three or four tries before you decide. The first go is rarely the best one. Wash the diffuser bowl now and then, too, since product and lint collect between the prongs, and keep the dryer's back filter clear so it breathes properly.