The single best decision you can make to secure your crypto better is to get a hardware wallet. I know you've mentioned you wanted security advice for those who cannot afford a hardware wallet, but the wallets aren't very expensive nowadays, so if you can't afford one then the value of the crypto you are holding can't be worth much anyways.

Basic security common sense should apply always: 1. Keep your private key secure & don't share with anyone 2. take extra care when clicking on links to avoid phising sites 3. Avoid scams.