I'll concentrate mostly on Firefox since that's the most popular Linux browser. But most Firefox tricks will work in other Mozilla-based browsers, and some will even work in non-Mozilla browsers like Konqueror and Opera.
I'll start the series with my favorite trick that not many people seem to know about: Bookmarklets. If you're a regular user of Firefox, I'm sure you're familiar with bookmarks, and you probably have a long list of them. But you might not have seen their most useful form.
For instance, the default search in Firefox uses Google. That means anything you type in the regular URLbar that isn't a URL will result in a Google search -- no need to waste space on a separate Google bar.
Google's great, but what if you want to search with Yahoo and see how it compares? Of course, you can go to yahoo.com and type some search terms; but what if you do that all the time? A Yahoo search bookmarklet is just the ticket.
First you need a URL for your bookmarklet. Go to Yahoo, type in a search term like banana and see where it goes. Yahoo will take you to a URL like this:
Go ahead and save that as a bookmark, using Firefox' regular Bookmarks->Bookmark this page menu item. Trim it down if you want to -- http://search.yahoo.com/search?p=banana works just as well as the longer version.