This is a good question....

Deer seem to have as varied vocal patterns as people do, so there isn't neccesarily a good or bad way to grunt. You could grunt too loud, or too often however.

Here's a couple tips from my experience. When you see a buck, out of range, with no prospect of it coming in, a quiet, short grunt works best to turn him around. The reason for one grunt is you do NOT want him to pinpoint the actual location of the sound, just the general direction. If the deer does not hear it, increase the volume, with one short grunt. NEVER grunt at a deer coming your way, all you do is alert him to something, good or bad.

When blind calling, a series of three grunts works best, but direct the sound to a different direction with each call, and separate each grunt by 2 seconds. Keep the grunts short, and medium volume, you want to give the impression of a buck following a doe, and uttering a tending grunt. After grunting, remain as still as you can for about a minute, its amazing how some bucks can zero in on a grunt call.

The only time I use a drawn out grunt, is when rattling, and only towards the end of the rattling sequesnce. I cannot explain why, but this has worked for me several times over the years.

As much as I insist on having a call with me during bow season, I almost always leave it behind during the gun season, or at least call very little. I don't know about you, but when gun season opens in my area, the rut is usually winding down, and the increased hunting pressure puts all bucks on red alert. A grunt call, can sometimes turn a deer away, so keep this in mind as well.

Good luck!