Privacy Badger is a browser add-on for Firefox and Chrome. It helps keep your online identity private by preventing third-party trackers from tracking you across websites.
The whole thing is very user-friendly: Privacy Badger learns to identify malicious trackers as you browse the web, which means you don’t have to configure anything after installing it. I use it in conjunction with uBlock Origin. I like this combination because uBlock Origin blocks trackers found in user-generated lists and lets Privacy Badger catch the rest.
To install it, head on to the Electronic Frontier Foundation’s website. They’re a well-known non-profit that’s been fighting for online privacy since the early 90s. Check out their other projects, and make a donation if you have spare cash.