Prefetch
This tweak changes how Windows loads Firefox. If you prefetch the application it will start much faster. Edit your Firefox shortcut to read:
"C:\Program Files\Mozilla Firefox\firefox.exe" /prefetch:1
That will prefetch the required .dlls and make Firefox load much faster each time you load it. Just make sure to keep that prefetch code in the shortcut and to run it once per-reset for the prefetching effect.
What about this shortcut code? A word to the wise!
Prefetching, Firefox takes up more RAM then Internet Explorer by default. But if you prefetch Firefox, Windows will keep Firefox in memory so it will load faster. But remember, you have to run Firefox at least once to prefetch it, then it is faster until you reboot again.
Well, that's it for Firefox tweaking. Enjoy your new speed!