“Come” is one of the most important commands we teach our dogs.  It is a potentially life-saving word, too.  If your dog is running toward the road for example…
Dogs learn that they can ignore our commands at times.  They learn this because when we tell/ask them to do something and they don’t do it, there may be no consequences at all.  It is imperative that this is not true when your dog hears, “come.”  Here are some rules that need to apply to that word.
1. In teaching it: never say “come” unless the dog is already coming toward you or you have them on a leash or rope of some kind.  When you say the word, there must be no alternative but to comply.
2. Always make it very worthwhile for the dog to come.  When they obey, there must be a super fantastic reward awaiting them.  They must immediately get the reward.  There can never ever be any punishment after complying.  It no longer matters what they did that made you say the word, if they come, they must not be punished.  If you are trying to teach them not to do something, go and get them – do not use “come.”
3. Do not ask them.  Tell them.  Come is a command.  Stop asking your dog.

Helpful hints: 1. Use a unique verbal and a visual signal at the same time.  (i.e. whistle and raise your hand) 2. If your dog has already learned that “come” can be ignored, teach a new word with the same rules as above.