A heuristic is a rule of thumb. (If I do this, what will happen?). One of the most well-known and successful heuristics is John Fanselow's: Do the opposite. He suggests that, if we carefully examine what we habitually do in our classes and then try to do the opposite, we may stumble upon some interesting new ways of proceeding. There are many other heuristics worth trying. For example: Withhold Information, Reverse the order. , Combine randomly, etc...