Welcome to the forums! Have fun planning your first trip. If I could offer you any advice it would be the following:
-Be sure to plan out where you want to go and what you want to see BEFORE you get there. If you don't you'll simply be overwhelmed by all the choices when you arrive.
-If someone tries to hand you something or says "how about some free show tickets tonight" just keep on a walking. If they persit the correct answer is "we are not married and we are leaving tonight."
-If some girl starts to take an interest in you, she's probably going to want some of your money if things continue.
-Be sure to wear some comfy shoes. Even if you'll be taking a car, bus, taxi, train, etc. these places are HUGE and you'll spend a lot of time on your feet.
-If you get sick of walking and decide to take a SHORT cab ride somewhere and the driver gives you grief about it, threaten to call the Taxi Authority (TA) and that should put an end to that nonesense. Also don't just pick any cab in the line, go to the first cab. They've all been waiting for a while and all want tips. If for some reason the driver refuses you or you don't like him, then you can go to the next cab.
-Be sure to check out all the free shows/attractions. It's rough gambling nonstop if things aren't going well and it's no fun to spend your time broke.
I could go on and on but I'm sure others will have lots of good tips for you as well. I know you didn't ask for any but something about the Vegas virgin just makes you want to throw it out there. I hope you have a great first trip. There are tons of eating, gambling, shopping and clubbing options. I'm sure you'll have a great time.
Have fun and good luck!