As long or as short as you want it to be!!!
Seriously, the "rules" for dresses and skirts have pretty much faded into the wind.
However, if you want to stay traditional
It depends upon several things:
How long your legs are
The length of your torso
Generally, in a professional setting, a woman's skirt should hit at about 2 inches above the knee.
Personally, I am 5'6 with average leg lenght and I find that skirts off the rack fit that range nicely.
Since you are very tall, skirts longer than mid calf will have a cumbersome look.
Happy dressing!Answer 2
Depends on your mood and the situation. And your age. If you wear a shorter skirt, the general rule is wear darker stockings. Of course, summer changes the rules a bit.Answer 3
when you put your hands down by your side, around the tips of your fingers is a good guide