Unfortunately, my response is late. I hope i could still be helpful for your future pony tails.

 first of all, know how high or exactly where your patron wants her ponytail to be placed, then you will section the crown area into a square according to the lenght of the patrons frontal area, then clip it down.  your next step is with a flat brush with smooth bristles, you bring the hair from the nape up, then you brush one side up and then the other side into a ponytail, i believe a high pony tail.  then put some gel on a fine tooth comb or a tail comb smooth out the back and the sides and spritz it.  in order to cover the elastic band that is holding the pony tail, you must now take a piece of the hair from the bottom of the pony tail and wrap it around and attach it with a hair pin.  check the pony tail make sure that it is centered and smooth, you may place the patron under the dryer for a few minutes or if you have a diffuser you may use that in order to dry the the gel and the spritz which help create a better hold.  then the piece of hair that was left to the front is for the high part, you will back comb or tease it, smooth it out into the ponytail.  spritz it and sheen and you should have a celebrity ponytail.  take care and good luck