Passwords are not as secure as it used to be – especially if you use the same password for multiple sites. One way to remedy this situation is by using two-factor authentication method.
Two-factor authentication is a process which makes the users provide two means of identification, first being your regular password, and second through a predeveloped and memorized security PIN (personal identification number) or through a text message, or even separate mobile applications. Some procedures could even include multi-factor authentication, which would add biometric data such as fingerprint scanning or voiceprint in conjunction with the first two. Proponents of multi-factor authentication method argue that it could drastically reduce the incidence of online fraud including identity theft, because the victim’s password would no longer be enough to give the thief access to their information.
Nowadays, a lot of social networking sites such as Facebook, Twitter, and even Google, are using this method to secure your accounts.
Here is a video on specific steps to establish a two-factor authentication for Google (Gmail)
For Facebook, you can reference this post and enable the authentication through the Facebook security setting here.
For Twitter, you can reference this post and enable the authentication here.
Here’s a video illustrating the steps for Twitter.
https://www.youtube.com/watch?v=IsdvJI0AK5M
To enable this security feature for other websites, you can always reference this page or this page for more comprehensive list.