If you are running XP make sure to get, setup and use TweakUI from the microsoft site (it's under powertools when you search), otherwise if you are using Vista make sure to turn on focus-follows-mouse in Keyclone (since Tweak doesn't work under vista). Once you have either of these option working you will cut down on one mouseclick per collection as they immeadiately set the instance you are hovering over to have focus so instead of having to click once to enable the window and then once to loot you will just have to click to loot.

Another thing to make sure of is to always start looting in reverse order for collection quests, leave collecting on your main until last otherwise you may miss the sparkles to indicate items to collect...especially on group spawns like the dung in Nagrand.