11. Turn tabs into app tabs
One of our favourite features in Firefox 4 is its Chrome-style App Tabs, which take the idea of pinned tabs and improve it: when you make a tab into an App Tab, its tab glows when it's updated - so for example you might make Gmail or Google Reader into an App Tab to get them out of the way without missing any updates. Simply right-click on the tab and choose Pin as App Tab.
TAB IT: App Tabs enable you to pin apps such as your email out of the way. App Tabs glow when updated
12. Make App Tabs open automatically
Once you've pinned your app tabs, right-click on the tab and choose Bookmark All Tabs. If you want the current tab layout to launch whenever you run Firefox, go into Preferences > General and click on Use Bookmark to change the default home page.
13. Create Tab Groups
If you often find yourself with too many open tabs, organise them into groups. Once you've opened a bunch of tabs, click on the Tab Groups button at the top right of the browser. You'll see Firefox's interface change to a collection of thumbnails.
By default Firefox 4 puts everything into one group; to create another group simply draw it in the blank grey area using the mouse, or drag a thumbnail out of the group into that area. Unfortunately Tab Groups are a per-session feature: while you can get them back after a restart with the Restore Previous Session option, you can't currently save your groups to access them in the future.
GROUP IT: Tab Groups help tame tab overload by enabling you to create multiple groups of open tabs
14. Change the search engine
Fed up with Google or just quickly need to query Amazon? Click on the drop-down next to Google's logo in the search box and you'll see a range of available search engines. Just click on one to choose it. Clicking Manage Search Engines enables you to remove, re-order or add more search engines to the list.
15. Type to switch tabs
Instead of scrolling through dozens of open tabs, quickly find the one you want by starting to type the page's title or domain name. A little "switch to tab" option appears in the suggestions box; select it to switch.