Avoid being tracked – A few hints below

• Use Firefox.

For beginners
• Install add-ons Decentraleyes & Privacy Badger, keeping you free from the biggest monsters without further necessry interaction.
• Always log out of sites you are not currently using.
• Use random passwords, different for each site. To make this simple, use a password manager like FF’s built-in one for a start.

Medium level
• Additionally use Firefox add-on uMatrix (via Firefox add-ons)
This allows only first party access. You’ll have to manually allow any 3rd party site operating in the background. Very educative!

Additional measures
• Set Firefox’ privacy & security preferences as in image below.

Now you can press your back button.