Here are two simple tips to speed up Firefox, just implement them you will notice the difference for sure.
1: You may speed up Firefox significantly by limiting the size of its internal history database. Just go to Prefrences >> Privacy >> History. Now reduce the number of days for which the data would be stored in your internal history database. This would definitely lead to significant improvement in Firefox speed.
2: Now there is no need to select the tab and hit the F5 key for reloading the Firefox tab. Just download “Reload Tab on Double click“. It’s a great Firefox extension which will reload firefox tab with just a double click thereby saving time and effort both.