Nationality or Gender of Instructor

The race or gender of the instructor is completely unimportant. Do not assume a Korean Taekwondo instructor is better than any other instructor. Do not assume a male instructor is better than a female or vice versa. What matters is whether the instructor can instruct and inspire you to be the best you can be at Taekwondo

Aesthetics of Dojang

You do not want to train in a dump but otherwise the appearance of the dojang is not that important. Many excellent instructors are just starting their businesses and cannot afford the best location. Many times, being a part of a growing dojang and helping it expand is as rewarding as the training itself. 

Superfluous Stuff

A good dojang needs a clean, safe training area, punch/kick targets, punch/kick bags, maybe some mirrors, and maybe some mats. Do not be overly influenced by unrelated stuff, such exercise machines, weight room, hot tubs, tanning beds, etc. If you want to pay for all these extras, that is okay, but they are unnecessary.