In my opionion  putting a 2FA  is one of the safest way to keep your account secured use password with ramdom numbers and letters. And keep uour private key in a safe place.

Hope this helps

safest way? theres a lot of safest way dude, first don't trust anyone/anybody that involve in bitcoin, because we all don't know when your bitcoin grew and that somebody who knows that you have much bitcoin are the one who can stole/hack your account, I hope not. second, secure/hide your (seed) private key that can fully control your bitcoin wallet in the safest place you've ever knew and don't let someone knew it. third don't use only one wallets, I mean use multiple wallets where you store equally your bitcoin to avoid loosing all your bitcoin at once.

activating 2FA is another solution to make sure our account secured but don't forget to keep safe the code. the other way is you can safe your bitcoin in one computer which not connected with internet and only you will know the place for safe the bitcoin. if you want to save in your android phone, i think its better that you buy one new cellular phone, install the wallet, send your bitcoin to that wallet and don't use the phone for your daily activity. i think it will safe for you and you only use if you want to sell your bitcoin only.

There's many way to earn bitcoin. But for me the safest way to earn bitcoin is to join in the signature campaign. In this campaign. You'll just need post about the topic or discussion in the forum,you just like talked to other people give your opinion about the topic its no risk unlike the trading mining and gambling etc. So for me its the safest way to earn bitcoin.

any bitcoin wallet. then save wallet dat file by rar with password   and save to gmail. enable 2FA verify

buy a private wallet
and keep you password in different places
probably you need some extra authentication as well 

Offline wallets, Ledger nano or trezor are the all in hardware wallets for storage of btc.

I store a lot of backups in the cloud storage.

just need to be careful if we are too scared and use all security it will not guarantee if we use internet with no smart ,
too much crime over the internet now and our security is our own for this point.