"The research suggests that the best way of swatting a fly is to creep up slowly and aim ahead of its location."
Well, duh. I bet those researchers spent months trying to work out how to get the last ship in Space Invaders too.
Experience tells me that a good flyswat (one that doesn't push air in front of it as it moves - that's important) and a modicum of dexterity are the main things needed to hit a fly. With practice you can even remove the head and leave the rest of the body intact, although it's not pleasant to clear up.