Witness Preparation: Best Practices for a Successful Deposition is a really nice article by Tulsa, Oklahoma attorney Robert P. Redemann. I strongly recommend it to any lawyer, even those who might not be involved with depositions. Sometimes it is good to understand best practices in our profession. Share the link with a young lawyer you know.
I would add one other item. Have you looked at the materials you routinely give the client to prepare for a deposition recently? Surely all law firms have progressed past the point of giving clients photocopied deposition tips in favor of custom-prepared materials with the law firm's name, address and logo. But if you have not reviewed your handouts lately, take a look. A good proofing and freshening is often in order. Use some different sized fonts, headers, text boxes or insert a small graphic or two to increase readability. You never know who may be looking at this document sometime as a representation of your firm's work product. Make this a professional document you are proud to have carry your firm's name.