Set sensible login options
TURN OFF AUTOMATIC LOGIN
One of the most important things you can do is also one of the simplest. Go to Users & Groups and click Login Options. From there, make sure ‘Automatic login’ is set to Off. Your Mac will now ask for a password every time you start it up.
NAME AND PASSWORD
When you have multiple users, your Mac may show a list of accounts on the login window. In Login Options, change ‘Display login window as’ to ‘Name and password’ so would-be intruders have to know a username as well as a password.
TURN OFF PASSWORD HINTS
While helpful, password hints can also be a liability by providing clues to your credentials. If you have a good memory, turn them off by clicking Change Password in the Users & Groups pane and removing the hint.