Dealers:
Players usually tip dealers by placing a bet for them (if the bet wins, the dealer keeps it). The amount and the frequency is up to you.

Change Persons, Keno Runners, Sports & Race book Personnel, etc.
Giving a portion of your winnings (5-10%) is standard practice. It also doesn't hurt to tip a dollar occasionally when you don't win.

Bartenders & Cocktail Waitresses:
A dollar a round for a small group (1-4 people), increasing the amount considering the number of people in your party and the kind of service you receive.

Bellmen & Bell Captains:
The amount of the tip depends of the amount of luggage that they have to haul up to your room. $2.00 per bag or $5.00 for 3-4 bags is standard. Any extra services the bell desk performs for you (travel arrangements, phone calls, flower delivery, etc.) should also be rewarded with a coupla bucks.

Room Service
The same as you would tip in a restaurant-15-20% depending on service.

Maids
Leave $1-$3 Dollars per day in your room for good service.

Showroom Maitre d' & Ushers:
In many of the Vegas hotels, showroom seating is now done by reservation. In the few that still leave the seating up to the discretion of the Maitre d', a tip of $10-$20 for a dinner show should put you where you want to be. Check your bill to see if a tip has already been automatically added in. If not, consider giving a small tip ($1-$5) to your usher for courteous service.

Valet Parking:
Free valet parking can be found at every major hotel. A tip of around $2.00-$3.00 to the attendant is standard. Also, remember $5.00 at the pick-up window will ensure you car is pulled up quickly on a busy night.