Alex at 2010-08-23 12:10:52:
for me, i have a would-i-keep-reading-this-if-i-were-a-contest-judge test.
it's a simple and surprisingly useful way of looking at a script or, really, any piece of writing. you have to have someone want to keep turning the pages, or else you're really in trouble, no matter how thematically interesting your work might be.
i really evaluate my work page-by-page, is this dramatic? is there tension? is there a reason to find out what happens next? if yes, keep going. if not, think more.