1. Use offline spreadsheets to register your accounts, use 1 raw for each account.
Can you expound more on what you actually mean by this? If you meant saving your login credentials on spreadsheets then that's definitely a big no.
The idea is to use offline spreadsheets, only if the device where you store your sensitive data is never going to be connected online ever!
This can really help because there are lots of online spreadsheets that can really be hacked because of some important information you have used and it is vulnerable since you are connected to the wireless area network or we can simply say internet. Once you are connected online, you should be careful of the things you are opening online especially websites, links, and ads. That can give the hackers information about you if that is really some suspicious link or website.
If you hesitate to use those softwares, you can save those things off-line. Make sure to check their correctness and re-useability after backup.
Good point, always the users need to test their passwords or private keys before sending funds to it. If there is any minimal finder mistake you won't be able to recover your coins, better to test and be sure it works as intended. And never send big amounts on the first tx, always test sending small tx, if all goes fine then send the intended amount. So far in crypto there is no way to reverse a tx.
This is also one of the things you should consider, this is obviously important but to remind every one of you, this can be great. Because sometimes we are forgetting to save private keys or passwords of your wallet. You should also double-check every information when you are sending funds because one simple mistake, that money cannot be sent to your specified wallet address.