For the bulk of my portfolio, I follow the investing method of BetterInvesting, which is essentially a kind of GARP analysis. I do also invest in early stage and turnaround opportunities, too, but those are much more laborious to study and understand properly.
Portfolio management is important, too. I have found an interesting complication since FIRE'ing, trying to trim my winners who have exceeded portfolio maximum, which also managing my taxes and ACA spending. If I was all tax-sheltered it wouldn't be a problem. And while I have managed in the last year, I can see a point in the future where my taxable account may get bound up in all winners, not just causing income to jump but also keeping me from investing a lot of the taxable account in new ideas. Something to noodle on as I gain direct experience.