When I'm thinking about a piece — examining my own work, or giving feedback/critique on another piece — I like to think about the structure using the analogy of the layers of the earth. You probably remember from elementary school seeing a cross-section of the earth: the red-hot core at the center, the rocky mantle surrounding it, and the relatively thin crust which covers everything.
Each show has its own "layers" — and if you feel that the little world you've created isn't spinning quite properly, there are different places to investigate to see why that might be.
At the center of everything, of course, is that "burning core" — the passion that drives the show. This is not the "meaning" or "message" (ugh) of a piece — this is the fire in you that caused you to write it — the fire/passion/energy you hope to pass on to the audience.