lok at the faces of the people dining - are they relaxed, seem happy, place seems lively, waitresses seem happy?
Does it look clean as you go in?
Do they have any "local newspaper taste test" articles in the foyer?
Is it easy to get a table on a saturday or valentines day?
Is the lighting down so low you cant see what is on the plate?
Do you see people fo that type eating there?Alwass a good sign.eg Chinese in chinese restaurants, italians in italian restaurants, etc.