browser features I use a lot but that not many people seem to know about:

• Ctrl+Shift+T (or Cmd+Shift+T for Mac users) reopens the most recently closed tab. On Firefox, Ctrl+Shift+N reopens the most recently closed window, too.
• Right-clicking selected text brings up the option to search for the text in your default search engine, very useful for quickly finding a definition.
• Alt+Left and Alt+Right navigate in history without reaching for the buttons.
• If you're using a touchpad, many desktop browsers have nifty multitouch controls like navigating history by sliding two fingers right or left, and touchscreen-style pinch-to-zoom (not the same as regular browser zoom %, it actually zooms into the viewport instead of just increasing element size!)
• Ctrl+L brings up the address bar and Ctrl+K brings up the search bar. Nowadays, these are usually the same bar but the behavior differs still! Ctrl+K will make sure whatever you type actually goes to the search engine even if it looks like a URL, very nifty in some cases. It even works if you've already started typing and want to change between URL and search.