I’ve brewed beer at home for several years. It took me a long time to realize that the screw-ups that occurred weren’t something to stress out over, but rather something to learn from. There seems to always be something new I “learn” each homebrew day. I’ve read several homebrew books, which are great for teaching you technique, but there are little tidbits that would clutter up a book, but if a friend relayed to you from their experience you’d be greatful of avoiding the same mistake.
There’s a quote attributed to Thomas Edison while he was trying to create the lightbulb (or some other great invention). He noted that he hadn’t failed, he simply had learned 1,000 ways how not to do it. With each successive bit of experience added in, your mistakes become smaller and less consequential. So hopefully some of these help you.