Using eCollars
I have never owned one, but have hunted with friends that use them. I have read several training books, and understand that it is a reinforcement tool, not a training tool. I will take any and all advice that you have to offer!
The dog must be trained and understand your commands before the ecollar comes into play. Also, start with vibration, beep, or other non-shock signal provided by the collar, and only shock the dog slightly at first, a "nick" at a low voltage setting, if it fails to obey the command after being vibrated. Precede the shock with the identical command. Commands, ideally, should be one syllable: come (or here), whoa, fetch, no, go (or hunt), sit, down, etc. or a whistle. Whistle training is good because if the dog is down range, the wind is blowing, or it is pushing through vegetation as high or higher than its head, the dog will have trouble hearing your voice command. That gets to the matter of hand signals. Ideally, you want to be silent while hunting. If you can achieve a reasonable degree of control over the dog in the field with only whistles (to get the dog to look at you) and hand signals - the arm extended for lateral moves and held straight up for "come toward me" -- you and your dog will be an accomplished field team. Dogs do not always obey commands in the field immediately, especially while scenting an area. Give them a little time to obey before vibrating or shocking.
Dogs vary greatly as to their reaction to being shocked. Based on my reading in this forum, some dogs react adversly -- retreating to the vehicle, refusing to hunt, etc. Obviously, a shock collar is not appropriate for such sensitive dogs. My Brittanys have never had a problem with it and shocking has been 100% effective in breaking them from rabbit and deer chasing.
Best of luck with your dog and have a great season.