It is really easy to change the advanced settings in Firefox, modifying how it works. In the address bar type:
When you hit enter you will get the ‘here be dragons’ warning, click ‘I’ll be careful, I promise’ and then we can continue.
Now you can see a whole host of options, ready to change!
First I’d get rid of the countdown when installing add-ons. To do this you need to edit the entry ‘security.dialog_enable_delay’, you can either scroll down to it or start typing it in the filter box (without the ‘). Then double click it and replace the number with a 0, to remove the timer altogether (alternatively you can enter a different number to wait a different amount of time (the value is in milliseconds)).
Secondly, when using the search box in the top right side of the browser, I prefer the results to open in a seperate tab (otherwise I just visit the Google homepage). To make this happen, you need to edit ‘browser.search.openintab’. Double clicking this will change it from False to True.
The final tweak that I will mention (but you can change a whole lot more) is the automatic text finding feature. Usually you would hit Ctrl+F then start typing to find text, however if you change ‘accessibility.typeaheadfind’ to true (again just double click it). Then you can just start typing text when you’re on a page to make the find box appear automatically and start searching for the word(s).
That is all I will run through, but you can change plenty of other things, including the number of suggestions that appear in the address bar (browser.urlbar.maxRichResults) and speed up your mouse scrolling (mousewheel.acceleration.start).