Nothing looks worse (to us) than seeing center isle carpet, a strip of concrete and then our mat.  Ideally you should try to get your mat to be right up against any carpet in the center isle and let the dead space be on the back or side of your space, where it can be hidden by your display fixtures or drop curtains.

If you are using sloped borders, you can use a piece of two sided carpet tape or duct tape on the bottom of the mat to keep the sloped corners from separating where they join at a 45 degree.  Two-sided carpet tape also works well at keeping the leading edge of your mat down if you are in a hall with no carpet and you notice people are dislocating the standard edges by kicking them.

Wipe your mat down before the show, and every night at the end of the show so it will be clean at the start of each day.  We won't mention any specific brands, but many customers are reporting good results with the flat mops with the disposable damp pads to keep everything looking great for the duration of the show.

If you are not going to remove your mat from the box and clean it before the next show, wipe it down good and let it dry before putting it back in the box.  You won't appreciate any surprises at the next show.