Here are a few ideas from the experts:
Visit Mozilla Update to get the latest information about updates, themes, plug-ins, and extensions.
Themes can be installed easily using either a drag-and-drop method or a small extension that puts an Install button on the Themes manager dialog box.
Any user can create a theme. If the theme is popular, interesting, or attractive, it can easily be distributed over the Internet.
This chapter showed the basics of creating a theme. The best way to get started is to simply start with an existing theme and modify it. This will teach you what makes up the theme.
Even though many plug-ins are available, do not try to install every one of them. Doing so can result in some unexpected interactions.
Plug-ins are used to enhance Firefox's capability to display content. Many plug-ins are available for Firefox.