Good article from Law.com about what not to do:
"’So, I’d really like it if you could say this …’
"If you’ve just said that to your expert witness, you’ve just made his blood boil. And that’s probably not going to be very good for your case. As engineer Steven Murray, Ph.D., of Exponent Failure Analysis Associates in Menlo Park, Calif., says, ‘Our job is not to support a lawyer’s theory, it’s to find out the technical truth.’
"Working on a case can be like a juggling act — you’ve got your client, the other side, the other side’s attorney(s), your witnesses, your expert witnesses, the other side’s witnesses and experts. That’s a lot of balls in the air. But you should never lose sight of your expert witnesses — they can make or break your case. Commit too many of the Seven Deadly Sins and you can sabotage your chances of getting the best results."
Very good read & important advice!