Here are some browser plugins that are effective and have been in widespread use for several years now, and work well with Google Chrome and Mozilla Firefox.
Please see the plugins/extensions part of the settings part of the browser in order to search and add them:
Free and open source plug-in that hides adverts on websites. Preferred to ABP (adblock plus) because there is no way for sites to pay to be added to a white-list.
You can manually add exceptions for any annoying parts of sites that get through, and can whitelist any sites that you feel happy to see adverts on in order to support the owner/company.
Again free and open source, HTTPS Everywhere fixes HTTPS problems by using clever technology to rewrite requests to sites in HTTPS.
This means that for example, if you’re using a wifi connection that isn’t your own, it is a lot harder for anyone snooping on the connection to see your content.
Free - blocks and stops companies on the internet from tracking your activity. This is really important for maintaining privacy.