At least in the initial drafts, efforts to keep a document concise may stifle the flow of written words. 
If this is true, then let the words come freely and deal with wordiness later. Once the desired content is captured, a writer can turn to making the document shorter and otherwise more pleasing.
There are a variety of ways to shorten the draft to meet page limits:
- Check the margins to be sure the lines extend to the full permitted width and length. Extend the block quote margins.
- Create at least a table of contents even if not required. The table follows the caption page which is not numbered, and the table will be page i, so the text can fill the full first page 1.
- Shorten the signature block. The signature block and date can appear on the same line.
- Scan through the sentences to see if the same subject is addressed in more than one place so that reordering and combining will reduce the length.
- Is there a passage that no longer is necessary to the document? A discussion of the facts, for example, may have been borrowed from another document and may contain facts not relevant to the current document. Trim the facts to those that matter for this motion or document.
- Is there an argument that seemed great originally that now seems weak? If so, decide if it should be eliminated. A really weak argument can be seen as grasping at straws and can diminish the power of the other, stronger arguments.
- Address each paragraph in turn and see if you can revise it to shorten it by one line. Substitute shorter words for long ones, simplify the sentence structure, and reduce nounification. Sentences that begin “There is/are” can often be reworded and shortened.
- Looking at each paragraph that has only a few words in the last line, revise the paragraph to eliminate that line.
None of these changes affects the substantive content of the document. Many of these techniques are obvious to the judge and are not appreciated, so avoid using them unless necessary.
Image courtesy of Flickr by Sebastien Wiertz (creative-commons license, no changes made).