Look for gearboxes, Abused ones will crunch on gear changes or hard to slot in at higher revs.
Interior Trim Level you'll find the panels near the doors are usually faded, Door trims deteriorated around the cups.
See if the A/C is working if available.
Power side mirrors. Check suspension and exhaust leaks.
One other important thing. Get the owner to redline the car a few times, listen to see if it struggles or blows any smoke (whatch the rear view or side mirror) if they are reluclant to rev high.. its rings or valve stem seals are shot.