Stick this list at the top of every writing project.
1. Who wants what?
2. What happens if they don't get it?
3. Why do they want it now?
4. What is stopping them from getting it?
5. How do they fail to get it?
6. What are they going to do about it?
A technical gloss on the above questions, for those more comfortable with writing theory:
1. Who is the protagonist and what is his goal?
2. What are the stakes?
3. Why is the goal urgent?
4. What is the conflict? or Who is the antagonist?
5. What is the scene-ending disaster?
6. What is the protagonist's response to the disaster?
In thesis form: Given [situation], [character] wants [goal] because [stakes/urgency] and fights [conflict(antagonist)] until [unexpected failure] renders [goal] a nullity. [Character] response is to feel [emotion] and decide to [new goal and plan].
Sources: Dwight V. Swain and David Mamet
For more: "Storytelling Catechisms"