This should be FUN, FUN, FUN
It can be practiced many times in the day without even realising - calling the pup when dinner is ready, calling the pup for a fuss, etc.
While carrying out this training, ONLY call the dog to you for nice things - if your dog hates a bath then don't call the dog to you, go and get him instead.
NEVER EVER tell your dog off when they have just come to you when asked, even if
you have been calling him for an hour while he has been chasing every dog in the
park. If he comes back to you, reward him! Telling him off at that point will
just teach him to stay away from you when you are calling 'Fido come'
Some of the problems that can occur with recall are that many owners:
release their dog to play with other dogs and stand and chat with the other owners for hours on end - once your dog learns how much fun it is to gallop about with other dogs, the interaction you are able to offer may look decidedly dull;
don't carry toys, play games or do much to interact with their pet;
refuse to reward a prompt recall with play or food - they simply take it all for granted until they lose the recall altogether. It's not surprise that their pets become demotivated if there's no chance of a half decent reward - why bother to make the effort;
once they have lost the recall altogether have to spend hours out in the park trying to recapture their pet and once they do, often out of sheer frustration will physically punish their pet for it's "disobedience" - if you were a dog and this happened to you, would you hurry to be back beside this person?
Once an owner starts to physically punish their dog, the only direction that the relationship is going, is downhill.
Ten minutes before your dog is due to be fed, have a friend or family member lightly hold your dog by his collar.
Walk away with the food bowl to another room.
Call your dog's name and "Come" in an inviting tone.
Entice him close to you and then put the bowl down for him to eat.
Repeat once or twice daily for the next week.
It's guaranteed that within that time your dog will start to build up pleasant associations with the word "Come"
Take your dog out to the garden.
Call your dog's name and "Come".
Encourage your dog to come close, gently hold his collar and then give him a food treat.
Ask a friend to call him to the other end of the garden and repeat.
Call him back again, make it into a fun game, repeating the recall a maximum of six times - any more and it'll become dull and boring.
Practice this for a few days until your dog gets into the habit of only hearing you call once.
If your dog is sniffing at a patch of grass or needs the toilet, let him finish what he's doing first.
If, on the other hand, he is doing nothing in particular, but when you call, looks directly at you and effectively "blanks" you, there is no harm whatsoever in throwing a set of keys along the ground to startle your dog. Take care that your dog never sees you throwing the keys and, of course, they should not strike the dog at all. What your dog will learn from this is that if he "blanks" you, a missile will fall out of the sky, landing at his feet and giving him a fright.
Also practice this with some friends/family - make sure they've all got pockets full of treats, put the dog on the line and stand close enough together that he can reach each of you whilst still on the line. Now take turns in calling the dog -he gets a treat when he goes to the person who's calling him.
Remember, when you want the dog to come to you, you should be the most exciting thing around, you may need to stoop down, jump up and down, run around in a circle, fall to the ground laughing or search for something in the grass. Acting 'odd' will get your dog curious and he will come over to see what you are up to you can then use your normal recall.
Recall can also be taught to a whistle. See Whistle Training