So an air-gapped computer+printer is best, and then protect the paper + computer from access and fire/water etc. No special stuff beyond that?
I ask because I want to store some keys that don't use BIP39/HD seeds to generate them.
You can also encrypt your paper wallet private-key with a BIP38 password, so anyone getting your paper wallet will also need a password to unlock it.
Bitaddress.org does that (check the 'Wallet Details' page).
What really matters is WHERE you're generating the paper wallet (so you need a trusted air gapped PC) and how you're printing this information (does your print save a history of what you print?, are you using a trusted address generator?). These are the main things you should focus.