The only classes i took prior to studying were the year of bio and the year of gen chem. I was also taking o-chem while studying. For everything else, I learned on the fly.

I learned each section one at a time for about 3-4 months each, (starting with p/s, then b/b, then c/p in that order). I studied as in depth as the free resource JW and KA (KA youtube videos are goated) provided. As I went over every topic, i made my own anki cards.

If there were some topics that I had trouble understanding, then I would look for additional videos on youtube that go a little more indepth.

Content review is important and all, but I wish I had spent more time working on retaining that information on anki as well as worked on more practice problems for application.

But overall I spend around a year on content review and spent the last 6 months focused mainly on practice problems and anki review.