[3] Do your own research on your interest coins, to find out about their wallets, and choose best ones in case you buy them and withdraw coins from exchanges
Best thing is always going the official website of the interest coin, they have always their official wallet or recommended wallet/s.
[5] Testing seeds, private keys, wallet backup first, and only deposit money in those wallets when testing results are good
Good practice is to turn off your internet connection when testing. Even its desktop or in mobile devices.