When writing an original low-budget script or rewriting an existing script to lower the budget, it's important to keep in mind that the script isn't really about the big-budget elements. Granted, certain subjects are difficult to tackle on a low budget, so some scripts or stories simply can't be "low-budgetized" without drastic changes. But many can.

The key is to focuson what each scene is saying rather than how it is saying it. Locations can be changed, special effects can be removed or minimized, crowd scenes can be cut entirely, but each scene's meaning and its place in the story can be preserved. The mob of CGI monsters attacking the protagonist on Times Square can become a single menacing attacker on a jogging path -- retaining the emotional content of the scene and the conflict and suspense that keep the audience glued to the screen. Some of the external trappings of the story may change, but the real story, the protagonist's journey, can remain the same.

When writing low-budget, it's also good to remember that as fun as big scenes are, little scenes can sometimes pack even more emotional punch. For a well-known example, take Monster's Ball. While it wasn't a big-budget movie to begin with, it did have a lot going on: deaths, prison, eviction. But it's the simple scene with the ice cream that everyone talks about.

The key to writing low-budget is to focus on the important elements of each scene -- emotion, conflict, suspense, resolution -- while working within the parameters of your budget.