ok so you know teh lightning spell and how when you have one enemy you kind of just hit them wait hit wait hit wait ....
well if you have two or more enemies (or an enemy and a group of villagers...)
just lety it aim its self (dont lock your aim) then as fast as you can toggle between two enemies (or a non enemy) and you should be able to hit them repeatedly with out waiting a second between each hit (plus it kills at a must faster speed)
if this was already known i didnt know .... (i found this out when at dark wood marshes yesterday and i basically made teh lake flood with lightning when i went to atatck the exploding mushrooms with lightning but forgot to lock it and it just made a wave across the whole thing)