If you are not the only user who has access to your site, be careful when setting up new user accounts too. If you have many users, you could limit their functions and permissions. They should only have access to the functionalities that are essential for them to do their job.
Force Strong Passwords can help you with this issue too. By default, WordPress recommends a strong password, but it won’t force you to change it if you’re picking a weak one. This plugin won’t let you proceed unless your password is strong enough. This could be a good solution for all the people who enter your admin. Essentially, it is your only way of making sure that they use strong passwords just like you do.