There are four motor mounts. The one on top by the passenger side fender holds that end of the motor up. There is one hidden under the battery tray, that holds the end of the transmission up, and bolts to the side frame in the engine compartment. To see it you have to take out the battery and unbolt the battery tray. Then there are two motor mounts on the sides of the transmission & near its bottom, that really keep the engine/transmission from twisting. The one in front you can see if you look below the upper radiator hose. The one in back is pretty well hidden, but is in the same relative position as the front one. They both are supported by a little subframe that runs from just below the radiator to behind the engine compartment. This subframe has to be unbolted and lowered when you want to change the transmission fluid and its filter. (And you need to put a jack under the bell-housing of the tranny to hold it up, or your wont be able to get the subframe pushed back up to bolt it back in).
The motor mount on the back side of the transmission (toward the firewall) commonly gets coated with any oil leaking from the engine or transmission, because of the air blasting back as you drive on the highway. This will soften the rubber of the motor mount, and it can begin tearing.
So if you see that a motor mount is visibly torn up or oil soaked - its bad or going bad. However it will never result in the motor dropping down much or twisting out of position, but it may cause some increased vibration or motor noise at times.