I can say that the safest way to access MyEtherWallet is using PRIVATE KEY. Because unlike passwords, private key has more digits and characters with a Upper case and lower case letters that MEW given to you. It is impossible to memorize it in a second. The only thing you must do before accessing MEW is to ensure that you are on the correct site of MEW. Because it concerns about coin and tokens or money, there are fake sites trying to hack MEW accounts or MEW wallets and get the tokens you have. before accessing or opening your MEW wallet, BE SURE THAT YOU ARE ON THE CORRECT MEW SITE TO BE SAFE.