Been there to play a couple of times. It kind of looks like a pool players paradise, but just imagine just about any pool hall that you show up to for a league match on a night that just happens to be the busiest night they've ever had. I think if you don't take it too seriously you're much more likely to have a good time and enjoy your experience. Stay loose and you'll play better and probably finish higher. There will be plenty of "enthusiests" already there, too many rule book fanatics, equipment snobs, avid billiard encyclopedia readers with too much worthless knowledge that will try and educate you if you let them - talking pool is one thing but some of these folks are like fanatical christians trying to force their beliefs down your throat, you'll also find plenty of people with way too much experience that are never to shy to let you know it. So the assh0le quotent will be reasonably high. But you'll also meet some really cool people that love pool and love to play and want to have a good time. I went to a local hall late one night and ran into a team from another part of the country, we had the best time, but it was away from the Riv, funny how that worked.
I would suggest find a good bar, without pool tables, with a hot bartender. Tip her well, eat the bar food, drink the $1.00 PBR's, don't be to shy to buy a round for the other pool players that find their way in there, or the locals that are sharing their bar stools with you, and at 2, 3, or 4 AM, when the strip is not that busy, if you're not the far away take time to walk back to your hotel (which hopefully is NOT the Riv or Circus Circus), walk through the Cosmopolitan, The Mirage, Ceasers, The Wynn, walk back and take time to appreciate the lights and all the things there are to see.
When it's time to play, be devoted to it, give it your best and don't hold back. When you match is over relax and enjoy yourself. Even if you don't qualify you should make the trip anyways.
Couple of tips, at The Cortez - rotten hotel, excellent steak house, and try to save one evening time to get downtown, it can be a real hoot.