What could happen now?
What is the most interesting thing to have happen now?
What is the most likely thing to have happen now?
Then comes the important part: "Given this character, in this situation, would s/he really do this most interesting thing?
If the answer is "No", then you have to change the imperative to make it work. That is, you fix things so the obvious thing (which is usually not interesting) becomes impossible or less likely. For example, if people are outside a burning building, the most likely thing is for them to stand there and gawk. The most interesting things are either to leave immediately or else to enter the burning building. Under what circumstances would the character choose one of these interesting alternatives?