It was mostly 10-15 minutes of dry fire about 3 times a week. Ben Stoeger's Dry Fire Reloaded has lots of good exercises.

If you do it longer, more frequently, you'll improve faster. I took the long route to get good (8 years in and I'm not even Master class) because I never really did any sports competitively when I was younger. I had to learn how to learn and learn how to actually get good at something. I had really coasted most of my life before this.

When you go to the range to practice, practice difficult target presentations and at difficult distances (15 yds should be your default distance). I think a lot of people practice the easy stuff (open target at 7 yards) and leave practice feeling really good about themselves, then go to a match and do badly. If you aren't leaving practice feeling like you suck you didn't actually challenge yourself.

There's a huge mental part to shooting USPSA that took me years to be proficient at. I would get lost halfway through stages, literally did not know where I was supposed to go next. I would miss targets, miss positions, and felt like I'd never be able to memorize a stage. Now, it's second nature. I never figured out how to speed this part up, so it came through just shooting lots of matches which is slow.

So, I think the main thing is to just keep plugging away.

I shot a match in 2017 where I finished dead last, probably my 5th match I ever shot and I sat in my car and asked myself "what the fuck am I doing here" and really thought about quitting completely. I had quit a lot of things in my life whenever it didn't come out the way I expected. But for some reason I decided that I wasn't going to be shit at this stupid fucking sport. So I went and bought an open gun and vowed to figure out how to practice and get good at the sport. By about 2020 I was consistently winning my local club match.