Winding Mechanisms
Most winding mechanisms have a key that is turned to wind the clock. Some clocks may have more than one winding mechanism. Some have a winding mechanism for the chimes, and others might have one for the pendulum and one for the clock spring. There are some timekeeper clocks that have two winding mechanisms for the spring. You cannot overwind the winding mechanism, as long as you are exerting normal hand pressure and not using some kind of tool to wind past the stop point. The spring will only wind so much before it breaks.
Broken Spring
Some people may think they overwound a clock because they keep winding a clock that has a broken spring. Over time, the spring may become fatigued. Often, people think they overwound their clock because the problem was more obvious on the day they wound it, but they actually need some sort of clock repair.
Friction
The most common cause of a clock stopping after the spring has been wound tight is the additional pressure and friction of the fully wound spring, which makes other parts harder to move. The holes in the clock plate can become elongated over a period of time from friction and metal shavings and become oval or egg-shaped instead of round. Often the additional friction from a tightly wound spring can cause this to become obvious and necessitates repairs on the clock plate.
Dirt and Dust Problems
Over time, dirt and dust in the workings of the clock can make it stop working, and sometimes this will happen when winding, because they can gunk up in the spring and workings of the clock. Don't use WD-40 on the clock because a clock-repair shop will have to remove the WD-40 before it can be cleaned with an ultrasonic cleaner.
Regular Maintenance
Keep your clock in good shape through yearly maintenance if it is an heirloom or grandfather clock. Of course, your clock may not warrant the expense if it is a cheap replica.