Experimentation, Reading Books and Talking to others in this hobby are perfect ways to get knowledge!
I know experimenting with lives is bad, but a lot of the time it works out

I would never have had my stocking without experimenting! I mean, if I didn’t experiment with taking a clam under my wing, I never would’ve had the beauty of my Deresa.
Reading is controversial. Sometimes the things you read aren’t up to date (especially with so many changes in species names), but the general care of the species never changes. No matter how hard that fish is, the general care will not change. It may adapt to suit the fish/invert’s preferences but it will never fully change.
And finally, Talk to others! Whether that’s online, in person or even just your LFS worker. We all know things and one of the things I say to others is;
Why have the knowledge but never share it?
It’s just pointless if you do that, your knowledge could change the care of a species but you may just keep it hidden. That helps nobody except yourself, I myself am not always a social person but if someone struggles with something, I will help them

I also thank talking to others, because if I hadn’t said this to anyone I would be ashamed to show this FTS.