Besides the rules of the actual game, certain unwritten rules of etiquette exist while playing craps and are expected to be followed. Many consider these guidelines as important as the actual rules themselves. New players should familiarize themselves with them before approaching a craps table.

Rules related to casino security

Players are not supposed to handle the dice with more than one hand, pass them directly from hand to hand, nor take the dice past the edge of the table. The only way to change hands when throwing dice, if permitted at all, is to set the dice on the table, let go, then take them with the other hand.
When throwing the dice, the player is expected to hit the farthest wall at the opposite end of the table. The dice may not be slid across the table and must be tossed. They may not be thrown higher than the eye level of the dealers.
The dice must not land in the boxman's bank or on any of the dealers' working stacks of money.
When either of the dice land on chips or markers not in the boxman's bank or the dealers' working stacks, the number that would be on top if the object the die is leaning on were removed, is the number that is used to make the call.
If one or both dice hits a player or dealer and rolls back onto the table, the roll counts as long as the person being hit did not interfere with either of the dice.
In most cases the shooter may "set" the dice to a particular configuration, but if they do, they must be quick about it so as not to delay the game. Some casinos have "no setting" rules, and the player must throw the dice as given to him.
Do not try to place money in the dealer's hand or expect the dealers to hand you chips. Dealers are not allowed to touch the players at any time. Players are expected to place cash on the layout and announce "change only" or a specific bet and amount. The dealer will then place chips on the layout or in front of the players.
Many craps table layouts state "NO CALL BETS". This means a player is not allowed to call out a bet without having at least the bet amount of chips on the table. If the chips exceed the bet, for example a $100 chip is placed and bets called out of "$25 on five and nine", the dealer will say "it's a bet" and return $50 change to the player. The dealer doesn't have to actually place the bet in the proper place on the table to constitute a valid bet. This method is consistent with the fast action of the game, allowing a player to make a last-second bet while the dice are about to be thrown. The NO CALL BET rule may exist to prevent confusion on the amount bet, possibly going back to the days of 25 cent tables. For example "three fifty" could mean $3.50 or $350. If the dealer is not clear about the intention of the player he may state "no bet" and push the chips back to the player.

Commonly observed etiquette

When offered the dice to shoot, a player may pass the dice to the next player without fear of offending anyone; however, keep in mind that at least one player must always be a "shooter" betting on either the pass line or don't pass line for the game to continue.
When tipping, the most common way is simply to toss chips onto the table and say "For the house," "For the dealers," or "For the boys" (the latter is considered acceptable even though dealers often are women). Another method is to place a bet next to your bet and call out "dealers." A "two-way" bet is one that is part for the player and part for the dealers. Usually, the dealers' bet is smaller than the player's bet, but it is appreciated. The part of the bet for the dealer is called a "toke" bet; this is from the $1 slot machine coins or tokens that are sometimes used to place bets for the dealers in a casino. Most casinos require the dealers to pick up their winning bets, including the original tip, rather than "let it ride" as the player may choose to do.
After the come-out roll, it is considered bad luck to say the word "seven". A common "nickname" for this number is "Big Red".
It is considered bad luck to change dice in the middle of a roll.
Center bets are made by tossing chips to the center of the table and calling out the intended bet; the stickman will then place the chips correctly for the player.
It is considered rude to "late bet," or make wagers while the dice are no longer in the middle of the table. While entirely permissible, excessive late betting will generally garner a warning.
Food, drinks, and other items should remain off the chip rail.
Players feel it is bad luck for the shooter to leave the table after a successful come-out roll.
When the shooter is ready to roll, players should remove their hands from the table area in order to avoid interfering with the dice. The stickman will often say "hands high, let 'em fly" or "dice are out, hands high".

Odds

The rules vary slightly from one casino to another, but the expected value of several bets is only slightly negative (the most favorable bets with the most favorable rules offer a house advantage of as little as 0.18%). All bets have a negative expectation except for the "free odds" bet that the player is allowed to make after a point is established on a flat (line) bet (this bet has a long-term expected value of 0). However, the "free odds" bet cannot be made independently, so the expected value of the entire bet, including odds, is still negative. Since there is no correlation between die rolls, there is no possible long-term winning strategy. While experienced blackjack players who learn to count cards can gain a small mathematical advantage over extended playing sessions by diligent study, there is no comparable strategy for craps.

Occasionally, players win several bets in a row; such players are said to be "on a roll." Those who increase their bets during a winning series can rapidly win substantial sums. On the other hand, money can be lost back just as quickly, as there is no statistical likelihood of a "hot streak" continuing for any given duration. To counter this, experienced players take full advantage of "free odds" -- bets on which there is zero house advantage. Maximizing the size of your odds bet in relation to your line bet will minimize but never eliminate the house edge. Many casinos have a limit on how large the odds bet can be in relation to the flat bet, with single, double, and five times odds common. Some casinos offer 3-4-5 odds, referring to the maximum multiple of the line bet a player can place in odds for the points of 4 and 10, 5 and 9, and 6 and 8, respectively. During promotional periods, a casino may even offer 100x odds bets, which renders the house edge to almost nothing but dramatically increases volatility. Horseshoe Casino founder Benny Binion once quipped that if every player took the 100x odds, the house "wouldn't be able to keep the lights on," referring to the overhead required to run casino games.

The only casino currently in Las Vegas to offer 100x odds is the Casino Royale located next to Harrah's on the strip. The Stratosphere offers 10x odds and most of the other casinos such as MGM and Bellagio offer 3x4x5. Some casinos such as the Riviera, Orleans and Gold Coast offer 2x odds which is considered an anathema to craps players, in equal footing with 6:5 payouts on single-deck blackjack. Most downtown casinos offer 5x (Binions) or 10x odds (Plaza, with the Golden Nugget offering the unusual 6x8x10 odds), while a handful of downtown casinos offer the horrible 2x odds (Sam Boyd's Fremont). Main Street Station offers 20x odds.

Casinos in other jurisdictions tend to be tighter or looser in the odds bet multiple allowed, largely in response to competition. For instance, casinos in Tunica, Mississippi tend to offer very liberal multiples, usually 20x or higher, because of the intense competition between the local casinos and also with Las Vegas itself. (These casinos often offer other rules favoring the player, such as charging commission on buy bets only when the bet is won, a practice seldom found in Vegas.) On the other hand, casinos in places where competition is not nearby, such as many riverboat casinos in the Midwest, may offer odds as low as 2x. In general, odds allowed in venues outside Las Vegas are more liberal, sometimes greatly so.

There are numerous middle market casinos whose income from gaming is negligible due to minimal chip size, and whose business model focuses on generating revenue primarily through the sale of alcohol. At such institutions, craps will often be rigged mildly in favor of guests, allowing the house to serve drinks to the large number of onlookers a winning table generates. Low limit Craps is also known to be used as a loss leader via the same odds to give the impression that a casino which derives its profits from gambling (almost all in Las Vegas) is full of winners and fun place to be, causing guests to play other, house favored games.

Optimal betting

One subtlety of craps is the variety in the house advantage on the many bets available on the craps layout. Of course the house always has an advantage on every bet, the house can win the player's money many, many times faster if a player makes certain bets. For example:

A player betting the pass line or come line at $10 per bet, 50 bets per hour, will lose on average $141 over 20 hours of gambling on a gaming trip.
A player placing the 4 and 10 at the same rates will lose on average $667 over the same period.
A player betting the "any seven" bet at the same rate will lose on average $1,667 over the same period.
The house percentage advantage is an indication of the expected loss per total amount bet. Note that the total bet amount also drives expected loss, so betting the table minimum will give the slowest rate of average loss. While odds bets lower the house percentage, they do so by increasing the total amount bet. Thus, given a fixed minimum pass line bet, the decision whether to make the odds bet or not does not affect the average dollar loss per game. It does, however, increase the variance, which improves the chance (though still under 50/50) that the player will be net ahead after a finite amount of play, as well as increasing the chance of larger losses or larger wins.

The table below gives house advantage of various bets, as well as expected loss over a typical gaming trip (e.g. 50 bets per hour for 5 hours per day over 4 days = 1000 bets)