To test for quality I like to try the Hot and Sour Soup, and the Special Fried Rice. These are common items with very many ingredients. The Hot and Sour soup allows me to know how well the Chef ballances flavour, and also if they are good with spicy things. The Special fried rice shows you how careful they are with simple food, and how generous they are with ingredients.
A good hot and sour soup will be both hot and sour neither taste overwhelming the other, and should have good crisp vegitables a nice stock base and nice ammount of ToFu. The Special Fried rice should contain plesant vegitables and pieces of pork and chicken that looks better than leftovers, it aught to also contain several nice shrimps, and egg that is not overcooked and not burnt.
The only over thing I like to know is that they can deep fry in batter propperly, and produce cryspy not soggy results. Orange peel beef is a good one for that, as is lemon chicken (which shouldn’t be too sweet) and even Sweet and Sour Pork (which is better if it is not dyed radioactive-red).
Once established that the restaurant is to my liking with such items, I would then go on to try the stranger/more exciting items on the menu on my secong visit.