One of the most important things you can do to improve your screenplay is to make the wording as brief and active as possible. A guaranteed way to make your wording less brief and less active is to fill it with adverbs, rather than choosing the right verbs in the first place. This usually happens when writers use non-descriptive verbs, such as “walk” or “go.” Instead of saying that someone walks slowly, isn’t it better to say that she meanders, creeps or lopes? Instead of saying someone goes quickly, isn’t it better to say that she rushes, bolts or hies? The right verb beats out even the most descriptive adverb every time.
The best way to remove adverbs from your screenplay is to do a search for “ly ” (for clarification, that’s “ly” followed by a space) and then replace that verb-adverb combination with a more descriptive verb. It’s okay to use the occasional adverb if you find that it reads better than any of the possible verb choices, but three adverbs that you should never (ever!) use in your descriptions are “very,” “suddenly” and “finally.” Those adverbs don't add anything to screenplay descriptions so be sure to remove all of them.
Though this change will probably not reduce the total number of pages in your script, it will make a noticeable difference in how your script reads. Even if the reader doesn’t realize that you went through the trouble to remove adverbs from your script, he will notice your brief, active word choices and will like your script better for it.