If your window air conditioner has a drain hole in the back--not all do--and it's not draining water, clear the drain hole and then clean the base of the unit to get rid of dirt that could enter the drain.
Leveling the air conditioner with a slightly backward tilt may also be necessary when you see your window air conditioner not draining water. The slightly backward tilt helps drain water flow to the back of the cabinet tray and down through the drain hole.
If you have a drain hose connected to the drain tray, check the drain hose for a clog when you see the window air conditioner not draining water.
