Extracting a dream theme is a powerful technique in and of itself. Indeed, some people have developed entire dream work approaches around the dream theme, even though there are slightly different ways to approach this method. Robert Gongaloff and Paricia Garfield have focused on universally occurring dream themes, and have tried to create an encompassing list of such themes. Mark Thurston and I were probably the first to write about dream themes back in the 1970, myself in a little article that was published in the Sundance Community Dream Journal, and Mark in a book that he wrote a year later. But Mark probably deserves the main credit for devising this simple, but powerful analytical method.
Mark and I have always thought that the dream should speak for itself; that is, the theme or process narrative (as we have called it in a recent paper that was published in the Journal of Creativity in Mental Health) should emerge from the dream structure, not be imposed from some predetermined list, however encompassing it might be. So our approach is to simply describe what's there--the action devoid of content. This approach is very similar to what family therapists do when they analyze the interactional dynamics of a family system. They believe that the specific content of a family's presenting problem is far less important than the way the family members are relating to each other. Not every family who struggles with, for example, a sexually active 15-year-old ends up in family therapy. Many families find ways to deal effectively with such challenges. So it's not the specific problem that causes the family's distress, it's the way they relate to each other around the problem. So a family therapist will observe how the family relates, rather than focusing on the content of their complaints, believing that the solution lies in changing how they are relating, rather than specifically addressing the content of the problem. Indeed, structural family therapists believe that the family will be able to address the problem effectively if, and only if, the family changes the way they relate.
Back to the dream theme. Dreamers are often "caught in the headlights" of the specific dream content. They are alarmed, intrigued, and otherwise preoccupied with the "what" of the dream, and thus do not see the underlying relational dynamics of the dream drama. For instance, if I dreamt that my boss was chasing me with a book, trying to hit me in the head with it, and I was able to avoid him by reciting his favorite poem, I might spend a great deal of time trying to figure out what a book meant, and what the particular poem meant. By focusing on the content, I might overlook the process narrative, which might reveal more to me than any association to the dream images might produce. The theme, "someone is trying to avoid someone else's aggression, and finally resolves the problem by appealing to his interests," could greatly expand my associations to the dream by temporarily diverting my attention away from the imagery. Not that we want to avoid the imagery, but unless we look at the underlying process at first, we may never see this dimension at all. When you effectively formulate a process narrative, sometimes the dreamer will immediately see one or more parallels in the waking life. It's a powerful intervention, and one that decreases the chances that the dream worker will project his or her biases onto the dream.
One other thing: You can state the process narrative from different perspectives. You can describe from the dreamer's perspective (i.e. someone is trying to get away from someone else...) or you can describe it from another dream character's perspective (i.e. someone is trying to catch up with someone else...). By stating the process narrative from other perspective, you help the dreamer get beyond a narrow view of the dream's deeper meaning, and look at his or her own behavior through the lens of another dream character. This multidimensional approach will support Gestalt dream work when you get around to working with the imagery (in Step Four of the Five Step Method).