Wow, So much I want to say here.
#1 Don't start with the shock collar? That is a horrible idea. I have seen what happens.
You will either have a dog with a broken spirit
(I think We have all seen one of those in the field before)
Or a dog that shuts down during training and just tries to hide under your feet.
#2 They are all different
Some dogs just have it from day one, some will really never have it at the level We want them to. Every one of them comes with instinct and the genes from their parents (good to bad. High dollar to mutt) After that it's completely up to us to teach them right from wrong.
I always remember when they are that age that they are a big piece of clay and He or She will be what I make them into. Go slow, one lesson at a time. If You go to fast or push the pressure up to high. Well damage can occur. It's better to keep at it but some times that means tomorrow.
My favorite Dog Trainer (RC) "pack a lunch when Your training a dog" It takes time and most of all patients.
#3 Food driven dogs are By far the easiest to train. Keep the treats coming as long as they are performing correctly. No treats for almost. add in a clicker used when the treat is given.
Pro Tip, I bring along a pack of Hot dogs as a secret weapon if needed. Kimber Loves a small Piece of hotdog. He will put cream and sugar in your coffee for a small piece.
#4 Do you use a release command at the finish of training. I make a big fuss when I finish training. I wait after the last command (sit) for a good time 60 seconds at that age.
Then I say "break!" and get all excited like the Seahawks just won the superbowl.
lots of pets maybe a surprise piece of hotdog, bit of wresling. He loves it and I believe looks forward to it during training. A reason to do a good job
I always finish on a perfectly exacuted command. I don't care if it's sit stay heal or kennel.
I always make it a surprise maybe really early today or after a command He doesn't Like (lay down flat head on the ground).
#5 someone else said this but I want to touch on it again. When It's work time (training) they have to stay focused and listen. Pro tip, Use a long lead like 50' if needed. Correction when needed. I just give a light tap to his hip or side with a firm finger. nothing painful, just a reminder that was wrong Let's go back and do that over from exactly where it went wrong.
one Last thing the good boy or treat or pat for a job well done during training needs to be small and quick. To much good job diminishes the well done to nothing special.
I hope some of that helps. Good luck with Your Dog.
I find that the ones that love You do much better than the ones that fear You.
Easy way to tell, Stop your dog out away from You, Tell them to sit, quickly walk right up to them and raise Your hand. If they cower (You broke their spirit) If they are excited and tail is wagging (They love You). If they don't really love You? Well don't forget to work on that part too. It's just as important.