Optimize Firefox (3.0.x)
Firefox can be manually tweaked by typing ‘ about:config’ in the address bar and then modifying the values of the respective fields of the Firefox control panel (i.e. the page that is displayed).
However, the easier way is to use FireTune, a freeware tool that helps to fine tune network related settings of Firefox.
If that is not enough, then you may consider the Configuration Mania extension to tweak many of the advanced (and hidden) settings.
Disable or remove any unused or unnecessary plug-ins, extensions and add-ons.
To minize page load time, I recommend to install these extensions:
Flashblock (to control Flash animation)
PDF Download (to control PDF files)
While Firefox can be instaled without (Windows) administration rights, you may encounter problems to install plug-ins. Here is some good advice to install the Flash Player plugin.