Next, select the Privacy tab. And if you want more privacy online, select the first option, Tell websites I do not want to be tracked, which isn't enabled by default. Although it can't prevent all tracking, it will reduce tracking by those sites that support this type of option.
Now, select the Content tab. To prevent pop-up windows that can be annoying and even contain phishing ads, ensure that the first option is enabled: Block pop-up windows.
Lastly, select the Advanced tab, select the Update subtab, and ensure that Automatically install updates is selected.
4. Use add-ons for more protection
Consider installing these security-related add-ons for extra protection:
Adblock Plus blocks banners, pop-ups, and video advertisements on websites to reduce clutter and the resulting annoyance; they can even reduce accidentally stumbling upon adware, malware, and phishing attacks.
Web of Trust (WOT) shows the user ratings of sites and blocks dangerous sites--such as those with malware--to increase safe surfing, shopping, and searching on the Web.
HTTPS Finder automatically detects and enforces HTTPS/SSL-encrypted connections when available--great in helping to reduce the chances of an eavesdropper on a Wi-Fi network from capturing your login details.
Xpnd.it! short URL expander allows you to hover over shortened links to see the real URL and other basic information about the site so you know where it leads before clicking.
5. Check and update plug-ins
Cyber criminals regularly use vulnerabilities in popular browser plug-ins (like Java and Adobe products) to infect and invade computers. Most plug-ins regularly release updates to patch security holes. Many plug-ins are set by default to update automatically or at least to notify you of them. However, it's a good idea to check periodically for updates. Consider using the Mozilla plug-in checker or third-party sites like Qualys BrowserCheck for updates for other browsers.
A little vigilance goes a long way
Firefox is pretty secure on its own, but you can make it even more secure with the right settings and add-ons. Good password management remains essential, too: Create and enable a strong master password so others can't use or view your passwords. And if you use the syncing feature to synchronize your passwords and browser data across devices, use a strong password to prevent others from syncing. Finally, keep tabs on your add-ons and plug-ins to make sure they're giving you the best possible protection.