Fact: At some time in the swim, you're going to get kicked squarely in the face. Deal with it. There's not much you can do to prepare for the crowded watery onslaught (maybe gator wrestling?), but a quality pair of goggles that suctions firmly to your face like an angry giant squid helps.
The TYR Nest Pro Nano did just that for us. We found the lack of leakage and the rock solid hold to be comforting, even if it does leave you with a wicked pair of raccoon eyes for a while afterward. They fit us perfectly, but we recommend first trying on a pair yourself. Looks aside, make sure you get the satisfying suction sound that confirms a good fit. [$20; tyr.com]