"The best placement for the ponytail will be somewhere between the crown of the head and the occipital bone that sticks out in back.
Look up as you brush the hair at your nape towards where you will place the ponytail. This step prevents the hair from sagging or being loose at the bottom.
Using a regular elastic band can make it difficult to keep tension on all the hair and to keep it smooth. If possible, use a bungee with hooks on the ends. You can also use a small elastic and put two bobby pins on it to create the same effect."—L'Oréal Professionnel Artist, Drew Schaefering