Make It Fun!
When you call a dog to you, 9 times out of 10 you are calling him away from something fun. One of the reasons a dog is going to leave something fun and come to you, is if you make it more fun. This means sincere and abundant praise, a surprise reward of food, a toy, a ball thrown, a belly rub - whatever makes your dog's heart sing. If you consistently dole out these favorites when only he comes to you on command, your dog will soon develop genuine enthusiasm for coming to you. Accentuate the positive!
Don't Punish Your Dog for Coming
If you yell at, scold, grab, shake, chase or hit your dog when he arrives, you have just taught him NOT to come to you. If you call him and he comes and you put him in his crate, clip on his lead, lecture him about chewing or do anything at all he considers unpleasant, you are training him NOT to come. No matter what the sin, no matter how annoying, no matter how late you are - if you call him and he comes, you must praise him.
Set Yourself up for Success
For the first few weeks of training, with some dogs longer, only practice the come command on lead or indoors where you are the most interesting thing going on. Call him to you, praise him and if he doesn't respond calmly go and get him, bring him back to the spot you called him from, praise him warmly. If he is slow to respond, try putting a treat under his nose, saying come, taking a step or two backwards and then rewarding him with the treat. He'll think that's great fun.
Don't Attempt the Impossible
Most people never practice the come command and then attempt to use it when their dog is chasing a squirrel, running off to parts unknown, or going to bark at the UPS man. Come is one of the more difficult commands to teach. It takes practice. Remember - if the dog won't come reliably across your living room, don't let him loose in an unsafe area. Too many of our clients have called us heart-broken because they "just wanted their dog to have some fun" and ended up with a tragedy. Don't take the risk. Keep him on lead or in a safe, enclosed area.
Use the Right Words
The command for come is "Dog's Name, Come." followed by sincere and enthusiastic praise. By using your dogs name in front of the command, you'll alert him to the fact that you are about to direct him in some way. If you say his name after you give the command, he's may look up and say "Yeah, what?" after the command is given.
Don't Change Words Constantly
"Come" is a command that people tend to get creative with. "Come here buddy, come to mommy. Over here. Come, come come." are not uncommon variations on the theme. All these words only serve to confuse the dog and a confused dog is rarely an obedient one. Keep things simple. If you are having a hard time keeping commands straight, just imagine how hard it is for your dog.
Practice
Although most of us want our dogs to be obedient, it isn't always easy to make the time to ensure that they are. Dogs only learn when you take the time to teach them. No practice, no learning. "Come" is a hard command to get 100% consistent response with because you are almost always calling the dog away from something he finds fascinating - like barking at another dog, chasing a squirrel, or rolling in something disgusting. Obedience when distracted is tough, but obedience when distracted may well save your dog's life one day. That makes all the effort well worth while.
Don't Wait for an Emergency
If you put off practicing and then hope your dog is going to respond in an emergency, you are going to end up with vet bills or worse. Just a few minutes of practice several times a week will get you an obedient dog who comes each and every time you call him in no time. If you have trouble getting the response you want, seek out the help of a qualified trainer or behaviorist.