I don't start with a tied ponytail as it is too neat across my head then...
I tip my head upside down, gather hair into place where i want the bun, twist up, still upside down right to the tip. Stand up straight again and twist around the base while holding the base. Fix with a band. I also use clips to secure the whole thing as I have very long hair. Not pins, but those little clips with pointy teeth (a bit like a Venus fly trap?!) can't think how to describe them!