What is the best methods to protect altcoin from hacker?
take care of your private key, passwords and dont click any suspicious link that has been sent to you through pm, shared on any social media sites, etc. the only reason why hackers have the access on your account is because they successfully get your key.
I keep my coins by holding them and securing them for long periods. it is very capable to make the coins safer and awake for long periods. so the coins I have do not have to worry about security in the future.