Offline. Put the wallet .dat files on a usb stick and keep them safe.
The USB Stick should be clean and free of viruses, or else it will be a mess for the user in case something bad happens (the data got corrupted/lost) to the USB stick. Also, a nice thing to do/consider is to have multiple copies of the wallet files in separate/different USB Sticks that are also free of viruses so that in case one got its data corrupted/lost, you will still have a copy of it.
Hardware wallets are best and modern idea of securing bitcoins. But not viable for everybody when we consider the cost needed for buying it.
A Password protection to encrypt your wallet is more than enough way to secure our bitcoins.
Password protections can secure yourself from primary physical hacking (Ie. having physical access of your computer). If you have a virus, it could record your password and spend your Bitcoins. A paper wallet would do the job of keeping your Bitcoins just fine.