Illegal Holds - There are several holds that the referee will penalize you for without warning. (There are other holds called "potentially dangerous holds" which the referee might make you let go of but will not penalize you for).
Technical Violations
Going off the mat or forcing your opponent off the mat to avoid wrestling ("fleeing the mat.")
Grabbing clothing, the mat, or the headgear
Locked or overlapped hands: If you are down on the mat in control of your opponent, you cannot lock or overlap your hands, fingers or arms around your opponent's body or both legs unless you have met criteria for a near pin of your opponent, or your opponent stands up and has all his/her weight on two feet, or you have lifted the opponent off the mat.
Leaving the mat during the match without the referee's permission
Reporting to the mat not properly equipped or not ready to wrestle, or equipment that is detected as being illegal after the match has started
Unnecessary roughness
Unsportsmanlike conduct
Flagrant Misconduct (ejection, the match is over)
Stalling (you get one warning before you are penalized and points are awarded).
Incorrect starting position or false start (You get two cautions before points are awarded).