Whether or not you win or lose at the casino, it is customary to tip your dealer, the same way you would leave a small gratuity for your server at your local greasy spoon even if you sent the blue plate special back to the kitchen. Here’s the protocol for doing so:
1) Put the tip on the surface of the table in-between hands (or spins, or rolls of the dice). Do not put it in a place where an inattentive dealer may assume that you are wagering instead of offering a gratuity.
2) Surveillance is always watching! Dealers are usually not allowed touch customers who are gambling at their tables. Most casinos forbid them from taking anything directly from a gambler’s hands.
3) Dealers are not allowed to directly wager their tips, but customers are allowed to place what are known as “toke bets” on their behalf. Place an additional chip next to your wager and say, “for the dealer.” If you win, the dealer will too.
4) Dealers at most casinos do not keep their own tips. The entire shift pools the accumulated tips for the day. Attempting to seek out an individual dealer outside of the pit may result in you getting yourself banned from the premises. If you really want an individual dealer to get proper credit, let his supervisor know how much you enjoyed him/her.
5) Tip BEFORE you decide to cash in your chips. Dealers may not be able to influence the results directly, but they are far more willing to prevent you from making a silly mistake if you've take care of them.
6) After an incredibly lucky run or huge jackpot, don't be stingy, or it may come back to bite you. You comp rating can ebb and flow at the whim of the floorperson. Don't give them a reason to "misplace" your rating.
Dealers provide a service, and you can't play without them. So, make sure you let them know they're appreciated.