1. Illegal Ruffing - This is perhaps the most common way to cheat at euchre. The lead player throws an off-suit and the opponent lays trump on it even though he is supposed to follow suit. The off-suit will be thrown in on a later trick in an attempt to go unnoticed. A person doing this will often mix the up the cards in the tricks they take to make it more difficult to trace in case the opponents catch them at it and try to back-track the hand.
2. Sandbagging - Trump is led and a player holding a lower trump plays an off-suit instead of following correctly. On a later trick, much to the surprise of the making team, the same player trumps an off-suit lead. This is a very amateur move because even mediocre euchre players usually notice when an opponent is void in trump. Throwing off a card of the same color does make it a little less noticeable though, and holding out the left bower makes explaining an "accident" slightly more believable since it is such a common beginner mistake.

1. Special attention should be paid to players' tricks that have not followed suit.
2. Players should demand that their opponents stack their tricks in neatly staggered piles.
3. Rules should be in place penalizing guilty parties at least 2 points for reneging (4 during loners) no matter if it is accidental or not.

1. High Mark-up - Perhaps the easiest way to score points is to simply mark the point up! Anyone who doesn't believe that the players in their friendly game would ever do this may be fooling themselves. I have often found that even honest players sometimes can't resist the temptation to mark 2 points for 4 tricks taken (especially if they took all but the first one), of course "accidentally". "Oh, you guys got the first trick? I'm sorry; I thought we took 'em all." Sound familiar?
2. Roll-back - Whenever two playing cards are used to keep score (probably 95% of the time) all sorts of "accidents" can happen. A little bump here, a sneeze there, even a blatant hand reaching over and unmarking a point or two. It happens all the time, believe it! Remember, no matter what the game is being played for, it is still a contest. People become competitive and sometimes can not stop themselves from cheating. Add money to the mix and the incentive only increases.

1. Mentally keep track of the score at all times. In the event that the scorecards are knocked over, you should know how to reset them.
2. For serious games, use pegboard style scorekeepers. Using 6's and 4's or two 5's (from the deck) is convenient; however, here is where the scoring mistakes are made!

1. Crossboarding - In friendly games, players often talk a lot. Sometimes the talk can be interpreted as "illegal" as it pertains to somebody's current hand. "Wrong color!" "Are you going alone?" "Damn, I'm bleedin' again!" These phrases may or may not be true and can slide in a friendly game. In a money game however, this form of "bull" talk will tend to cause problems, especially if the statements are accurate.
2. Signals - Rarely is someone suspected of signaling if they were in fact unintentionally making a motion that looked like something else. For example, clutching or holding chest (hearts), scooping or digging (spades), grasping ring finger (diamonds), hammering action (clubs) are all obvious signals that people who have never even met before could use to let their partner know what suit they want to call. Organized signaling can be a lot more cunning. Little movements with ashtrays, subtle facial expressions, winks, nods etc. can be worked out and practiced by a partnership who wants to tell each other exactly what each other holds.
3. Flashing (not to be confused with "flashwork", described later) - If the other team is not paying close attention to the game, flashing techniques can be employed. One of these scenarios might include;

If the players are relaxed and there is a lot of conversation going on, a partnership simply has to take turns telling loud descriptive (usually funny) stories complete with hand gestures to capture the full attention of the opponents. When all eyes are fixed on the story teller, his partner very quickly, yet smoothly turns his hand around, exposing it to the speaker. (below)

Of course, the "on - line" game of Euchre will not have most of the aforementioned situations; then again, we still play a lot of "live" Euchre! This is he arena where we must be vigilant !