I’d classify the “%s” feature of keywords as an intermediate or advanced feature, but the basic use (type mail in the location bar to go to http://www.myisp.example/webmail) is probably suitable for beginners.

For the beginner level I think its best to keep things very simple. An introduction to the tab structure and basic functions of the browser, some basic short-keys, customizing tools, and perhaps easing them into some simple add-ons.

A few favorites (so far) include:

- Adblock
- PicLens
- Dictionary Tooltip
- Google Maps/Directions
- ClipMarks
- Mouse Gestures
- Gmail Space

I also found some of the comments on this page quite helpful.

Beginner:
Get spell checking in webmail and community sites. Right click any text box and select a language.

Middle click on a link to open it in a new tab.

To clone a tab, drag the icon next to the address bar (favicon) to the tab bar (this is mega useful if you want to keep reading a page, but also go back to comment on what you are reading - e.g. slashdot or blog post)

Add wikipedia to search engine box.

Customize the toolbar, drag the bookmarks up so they are next to the ‘file edit history….’ menus. This reduces the GUI screen size.

Install SAGE for RSS cos it is SO easy to use.

If you do any kind of HTML or CSS install the DOM inspector and use the ‘right click’ -> inspect this element. Then click on the CSS rules that apply to that element (and the order in which they are applied). Best. Debug. Tool. Ever. Made.

Those are my MEGA tips.

monk.e.boy

Intermediate:
- add a search engine
- how to add web feeds
- how to add extensions/themes

Advanced:
- about:config: force close buttons on tabs, single close button on tab bar

Intermediate:
* Middle-clicking tabs closes them.
* Alt-enter in the address bar opens an address in a new tab.
* You can drag a link from a page to the tab strip to open it in a new tab, or in another specific tab (if you drag over it).
* In the Options menu, the first choice on the first pane is “When Firefox starts:”. Setting this to “Show my windows and tabs from last time” will make your tabs persist across restarts, so you won’t lose anything if you accidentally close your browser.

Advanced:
* Pressing shift-delete on an item in an autocomplete dropdown (the address bar, or a content-area dropdown) will delete an entry.
* about:config has many useful prefs:
** “accessibility.typeaheadfind.casesensitive” = “2″ will result in an emacs-style “auto-case” mode where searches are case-insensitive unless you type in mixed case.
** When on a broadband connection, doubling basically every numeric “network.http.*” pref will generally result in decreased pageload time.
** Setting “keyword.URL” to “http://www.google.com/search?ie=UTF-8&q=” means you can get rid of your Google search box in the address bar: now the address bar will automatically do a search for you when you type in something that looks like a search query.

Beginner:
* “Install this addon and $MAGIC_HAPPENS with no extra work”. For example, “Install Adblock Plus, let the browser restart, choose EasyList at the menu, and most ads will disappear”.
* “Press Ctrl-K to go directly to the search field, rather than using the mouse. Press Ctrl-L to go directly to the address bar.”

Intermediate:
* “Install this addon, and you can do $EXTRA_FUNCTIONALITY”. For example, “Install It’s All Text, let the browser restart, set your preferred editor in the It’s All Text preferences, and you can now click the edit button next to text boxes to edit their contents in that editor.”. Or “Install UnPlug, and then click the UnPlug icon in the toolbar to attempt to find embedded video or audio on the current page so you can download it.”
* “Use about:config to change this setting and $MAGIC_HAPPENS with no extra work”.

Advanced:
* “Go edit $FILE in your profile directory and $MAGIC_HAPPENS”.
* “Install this extension, and you can now write $CODE to do $EXTRA_FUNCTIONALITY”. For example, “Install Greasemonkey, then…”
* “Do this to make web development easier”