There are so many products in the market I could spend a fortune trying everything out!
it’s good to use the curl grade to get a guide - see pic - as some brands will recommend which grade curl they’re for which will narrow your choices down a bit.
Starting with shampoo/ conditioner
Teenagers do tend to get greasy roots so you need something cleansing that is not too drying - I use and love L’Oréal professional serie expert curl range and find its great for that reason - I’m a 2b curl
Aveda is good, Tigi ok but found it heavy long term, wella professional also good.
there’s so many on the market and hopefully others will post their recommendations
As for fighting frizz/styling - a Hair mask or conditioner applied onto towel dried hair and left to dry in is a good way to fight frizz. It’ll not look greasy or heavy like you’d imagine. I use L’Oréal revive dream lengths- sometimes add a bit of gloss serum and a squirt of mousse (Bumble and bumble mousse is great but a little expensive not drying though and last for ages ) mixed to a paste and drag through curls with fingers. (Don’t comb or brush curls after washing either)
Take large sections of hair and twist around your finger forming a coil so your pushing hair into curl probably 10 in total and air dry or diffuse dry really really softly.
air drying hair takes a while so you can always top knot it or plait it instead- use big sections and loose plait for a wavy rather than tight curl effect ( the larger the sections the looser the wave it’ll dry in)
There’s a few new air dry hair creams on the market that I haven’t tried yet - has anyone got any faves?
Beach style sprays tend to have salt/alcohol so are little bit drying to use long term but ok for a quick revive.
Mousse has an 80’s big hair reputation but it is still a good go to as long as you don’t go too cheap - some of the really cheap ones are awful - a good quality one gives great results but again depends on your curl grade.
also try aloe Vera gel is really good to soften curls.