First, consider the occasion. A formal night out requires a different type of skirt than a casual night out.
Second, consider the type of event. A night out at a club may require a more revealing skirt than a night out at a dinner party.
Third, consider your body type. A petite woman may want to choose a shorter skirt than a taller woman.
Fourth, consider your wardrobe. Do you have a lot of skirts already? If so, choose a skirt that you can wear again and again.
Finally, consider your budget. A more expensive skirt may be worth it if it will look better and last longer.