Password Managers
One very common way for a hacker to get into an account is by using information from an already-compromised service. You should always use a different password for each website or service you use, but most people have hundreds or even thousands of accounts so it becomes impossible to remember them all. Using a password manager means you only need to remember one password – the one for the password manager itself (so make it a good one). This way you can use the longest, most complex password each service allows and also use a unique password for each one.