LV is my favorite vacation location. I visit several times per year. Here are some sugestions of mine. All of these are predicated on your staying on "the Strip". If you are not doing that, repost and I will have some more.
(I assume this thread is exempt from the normal gambling discussion prohibitions from over at the Sports Page, if not, I appologize in advance).
Leaving the airport, tell the driver to NOT take the tunnel. Taxis can reach a hotel either on a surface street (Paradise Road) or via the tunnel and I-15. I-15 will run the meter twice as far. Consider a shared van or a limo. The price can be less depending on your party size.
You can check into the two big chains (Harrah's or MGM-M) in the airport. The line will be shorter there than at the hotel.
The monorail is a great way to move around, but remember that it stops in the very back of the hotels on the east side of the strip. Using it to go to a west side hotel can be a hike.
Taxis do not stop on the Strip. Rather you line up at the taxi line in a hotel.
The tourist oriented trolley (private) and Duece bus (governement) are good alternatives to the monorail as well.
Hotels, because of the sports gambling, do NOT offer free internet. If you have a cellphone laptop, take it, the in-room internet can add up.
NEVER pay for a drink of any type. The waitresses will be by. They are just as glad to get you a Coke as anything else. The higher class the hotel, the more frequent the service. Also, in a better place (Caesars, Bellagio, etc) ask for top shelf liquor and "premium" beers. The waitresses do not care to get you what you want.
There are two main chains. Harrah's (Total Rewards) and MGM-Mirage. Get a card from both, and from the indpendents (Sam Boyd, TI, Hilton, Venitian) and play a little at each. You will get unbelievable free offers for return trips.
The Harrah's casinos charge for drinks in the sports books, but the upper end MGM-M places do not (Bellagio, MGM, etc). At a Harrah's casinos, ask for a drink ticket when you place a sports bet or you will have to pay for drinks.
LV cops, and casino security, are serious people and mostly subscribe to the "move along" theory. Keep your shirt on (male or female), act nice, don't be an obnoxious drunk, and conduct yourself well and you will have no problems.
Go to the Freemont Street experience (light show). It is worth the trip, and drop by the old downtown casnios there for a couple of hours.
If you are not a west coast person, In-n-Out is not to be missed at least once.
Shopping. Plenty of it. I live in a small town, so there are lots of things there I do not see everyday. Remember that many places, especially clothing stores, want to dicker with you as in Latin America, and will come down on price. And, if you have it shipped, you pay no sales taxes. The bus out to the Primm mall is not worth the trip. The Fashion Mall (traditional mall) and the high end arcades at Caesar's, Planet Hollywood, Venetian, and Mandalay Bay are all great. Caesar's (Forum Shops) is my favorite.
Forgotten stuff (toothbrushes, aspirin, etc) is super expensive. If you have to, there is a Walgreens and a CVS near the City Center, and an ABC in the Miracle Mile.
Learn how to play games on line before you go, if you do not know how, and watch for the subtile differences in rules, and thus odds, between different places.
The Grand Canyon is your choice. If you are going by bus (or car) understand that it is 140 miles out in the desert with nothing between you and LV than the Hoover Dam and just dust and more dust. Hoover Dam is an OK trip.
Never pay full price for a show. Either ask for a comp if you are a high roller, or go to the many outlets of the tickets for less outlets which operate on a day of for far less basis as in New York.
Joe's Stone Crab. The greatest restaurant in the world. Ask for "Big Al" as your waiter. Worth every penny. Tip my good friend Al well if you mention my name.