I perfer to use the one shot and pull method. Too many times we believe that we shoot better than we really do.
We shoot a good arrow, then a bad arrow, then another bad arrow, then we shoot two good arrows. After the session you think things went better than they really did.
In addition, fatigue is a negative factor in development of form. The more fatigued you become, the more sloppy the shooter becomes. Soon your are practicing bad techinque, and once learned, it can take an "Act of Congress" to correct. So taking one shot, walking and pulling forces several things to happen. One, you get a real assesment of the shot. Two, you get to think about it, and make both mental and physical corrections. Three, you are getting to rest between shots. Some say it even contributes to the calling of one's shots. Which, when it ocurrs, is an indicator that you are well on your way to better shooting.
Another method I use is the bare bale method. That is removing all targets from the bale. I then move around the yard, and pick a specific spot and shoot for it. This aids in confidence when it comes to picking a spot on the real deal.
Even though, you most likely will be able find a tuff of hair, or a shadow, or crease. You can't always count on it. Especially on hogs, and bears that have coats that make that more difficult.
Shoot lots of good arrows when trying to develope endurance, shoot few arrows when developing form and focus. It really builds confidence, with is the intangible that is often over looked in good shooting.