Advise on building credit

My financial situation isn’t terrible but it isn’t great either. I own my car, it’s a used CRV I paid for in full from a private seller, so even though that’s a good thing, no car payments were ever made to build my credit. Almost every guest has a car note ruining their lives, so I feel really good about that lol.

I don’t have any debts but the problem is I also don’t have any credit, either. My credit score is just a dash. I know getting a credit card and paying it regularly seems like the obvious answer, but another thing constantly ruining these guests lives is the crazy high interests on their cards. The only credit cards I can be approved for have 25-30% interest, which feels crazy high. Idk I’m clearly not the most financially literate person, maybe that’s normal? Is the interest not the problem, but the way these guests use/treat the card? Any advise on how to build healthy credit?

I’m in a place with my finances where it can either continue to go horribly wrong, or I have the opportunity to pick myself up and do well. I think lol. I don’t want to say my age because it’s highly embarrassing I’ve gone this long with 0 credit, but I am 25 🙃 it was just never really a concern until my bf and I started planning to move in together. (He is fully aware of my situation btw)