I discovered a good post about depositions by Ernie the Attorney, which contains a link to Ernie's "Deposition Tips for New Lawyers." Ernie's deposition tips cover these areas: basics; preparing to take a deposition; getting the deposition started; on the record/off the record; common problems; and defending depositions. If you need the basics, read it.
Another blawg author to write recently about depositions is TPB at unbillable hours, who noted in this post:
I have changed how I ask questions at depositions based on how I want my questions to read on the printed page. My ideal circumstance is to ask a question and receive an answer that is a logical, complete quotation without ever needing the context of the rest of the deposition.
My view on deposition language is very similar. If you have a visual imagination, you should try to picture as you are speaking what the printed words will look like on the page. This will keep you from adding unnecessary words, which will clutter the deposition and make it useless for impeachment. And in keeping with TPB's suggestion, don't use prepositions like "he" or "she" or "they"--say the name. When you get to the point where you are pinning the witness down for an "impeachment nugget," the question should contain as much information as possible, without being unwieldy. (Practice enough, and it's easier than it sounds).