Well this is because every day more and more people have their Facebook account opened so it's proportional situation hackers will search for their target to see if their victim has Facebook profile or not, because it's more easily to open their inbox messages and read all private information they need.
1. The most used and dangerous method which hacked thousands of Facebook accounts in last years is a phishing method. A phisher is a false login site which looks exactly or very similar to the original Facebook login page. So if a victim logins to their account trough that, a hacker will gets their password in a email message or other ways.
- To recognize a phisher and secure from it you need just to look in the address URL bar of your browser and if there is any other domain but not official Facebook one "facebook.com" , like for example "gologintofacebooknow.com" then stay away from it! If you login you need to immediately change your account password else your account will probably get stolen.
2. Using see example: Facebook hacking app to get password These tools can be very dangerous and steal your password but there is also a very easy way to stop them: Make strong password contained of lowercase + uppercase letters + numbers + special characters and there is no way any software will break into your account.These programs use brute-forcing methods to get password, means it has a pre-made passwords list integrated in itself contained of thousands of words so it tries to login to your FB account multiple times until it get's the right one.
3. Use good antivirus software to prevent spying applications which you can download by mistake or various pop-ups from the internet. There are all kind of these apps designed to spy your activity on the web and some of them can also steal your stored passwords saved on your browser. Compare and choose the right antivirus software for your needs and protect your computer and Facebook account from dangerous hacking attacks which lurks behind the corner.
To prevent all other ways simply follow the next steps and you should be fine:
Set your account privacy settings by going to Settings in the above right menu. You can set who can send you message, who can see your profile etc. It's recommended to set all options to only be showed to people who you closely know. It's just your friends list. Else you're risking a some hacker can try to trick you with all they black-hat ways to get your information. If you're not skilled enough yet to recognize who to trust, I advice you to limit your privacy settings.
That's all from me by now. You can also take a look at short video for helping you to learn how to protect against FB hacking better.
Best regards and thanks for reading!