There is one suit layout that a new player should be very careful with, and that is when he holds a queen in front of an AJ or KJ tenace in dummy. For example:
Declarer leads the six toward dummy. Raw novices will take some time to think about playing the queen in this situation. A more experienced novice, on the other hand, might play the two as fast as he can, to pretend he doesn't have any problem. The raw novice is allowed to stop and think about the play if he is genuinely unsure of what to do; the more experienced novice who 'shotguns' the two is being unethical because he is purposely varying his tempo in an attempt to deceive declarer. To repeat, tempo should never be used to try to mislead one's opponents.
Another suit layout that beginners should watch for:
In this diagram we have swapped the nine and the queen. Again declarer leads the six. An unethical player will purposely pause before playing the two, in an attempt to pretend he has the queen. Be careful if you are a beginner and this situation arises. If it does, you are expected to follow suit smoothly. Even a slight break in tempo in a tournament may cause declarer to start screaming for the bridge cops. Whether or not declarer will be overreacting is not the issue. The point is to avoid any chance of a misinterpretation of your intentions.