Hi Dee
In addition to the other great advice you have received I would add 2
things: find out if there is an AV or IT person there to help and arrive
really early. Some venues will provide support people to get you set up and
make sure everything working (particularly if they have a complex set up).
And if you arrive really early the hook up will be very smooth and take
about 30 seconds, but if you arrive with only 5 minutes to spare everything
will go wrong ;-)
Oh, one more thing: if you use a dual monitor set up, I would return the
laptop to single monitor mode before taking it to the venue (sometimes my
laptop gets confused by being hooked up to a different second monitor than
it is expecting).
Lucy