My one bit of advice is to not look at tiktok since they’re steeped in microtrends. My favourite sewing channels are Rachel Maksy, Stitchess & Bernadette Banner (Stitchess also does alternative fashion). Your best bet is to look at what magazines are saying, what’s on the front of Fucking Young!, NME for example, or Vogue - but these are only glimpses into fashion itself. I personally don’t purchase clothes almost at all, rather I occasionally use thrifting apps like Vinted (though I picked up 4 sick ass pieces in a giveaway once). I repair or alter my own stuff and if you’re into punk, that’s very simple & there are tons of DIY methods out there.
For learning to coordinate style, I got Frugal Aesthetics, Kati Yoo & Fashion Elitist - they’re my go-tos for fashion tips & styling advice. They talk about building a wardrobe, timeless pieces & how to accommodate your shape. FA & FE are geared towards mens fashion tho. Searching for brands isn’t a huge issue, as the fashion houses & brands one needs to care about are the ones most featured in the articles - my personal fave collection this decade has been Schiaparelli’s Fall 2022. DSQUARED has also done some brilliant stuff on the runway.
Some YouTubers like Mina Le or Modern Gurlz cover video essays on rising fashion trends or dissecting fashion history, which is a whole genre in and of itself.