Your canine friend isn't just a house pet. Your dog is a part of your life, and just as you would want to have your children behave, so do you desire that for your dog because the whole household then runs smoother and more happily.
You must have patience as you train your dog, for they like to be a bit rambunctious and obedience doesn't come easily. Be firm but never hurtful as you teach what is needed. Violence will only make your dog more anxious and thus more aggressive.
In fact, perseverance is the most important thing. That's because whether you train your dog on your own, with someones help or with a handbook, any commands and tricks you teach your dog have to be repeated again and again. Only with repetition will the dog learn the trick. You need to keep doing it because dogs can be forgetful just like people.
Dogs need to be reminded and instructions should be repeated over and over. Once your dog is trained, however, he will only rarely require instruction. He will be well behaved and have a good temperament, and will be a dog you enjoy having in your home and can take in public without concern.
No one is bothered by a well behaved dog. They don't mind him coming into their store when they realize he obeys his master and won't create problems or make any sort of mess.
Dogs like to know who the boss is. They will try to take over if they are not sure who the boss is. Training a dog shows him who the boss is and allows them to confidently follow your lead. Training your dog has the added benefit of allowing you to spend time with him and will in turn strengthen the bond between you and him.
Look around for an obedience training school if you can't do it yourself. There are many good ones around. After a few sessions with your dog at one of these places, you'll find it much easier to command your dog and have him listen to you with no problem.
But it's important that you know your dog's capacity. As with humans, some dogs learn faster than others. All can learn, but some a bit more slowly. If you respect your dog's personality and feelings, he'll be able to try harder and you'll have the relationship you want.