In addition to what ssbbqjuy pointed out, another common challenge is time management. How long does it really take to prep all the sides, pull pork, slice brisket, setup of the serving line, etc. etc. The first few times you will probably find your self running around like a headless chicken. It gets exponentially more complicated when you add in employees that are supposed to be "helping".
Once you develop some standard procedures, things go much more smoothly and at a predictable pace from which you can create a work schedule so you are on time.