First, ditch the Flexi-lead or retractable leash if you've been using one. Your dog needs to be on a four to six foot regular leash for training "heel." Second, know that in the dog's world, there's only one Pack Leader, and anytime your dog is walking ahead of or in front of you, S/HE is the Pack Leader, not you. Third, keep in mind that if your dog has had lots of practice pulling on the leash or stopping at every tree or bush or generally doing whatever s/he pleases while on leash, it will take LOTS of practice to effectively teach your dog the RIGHT way to leash walk. Patience on your part, as well as a firm commitment to NOT allow the old habits to continue, will be necessary.
Okay, then. Let's talk about teaching your dog to heel. Heeling means walking BESIDE you on a LOOSE lead. Because most dogs respond to food lures/rewards, you'll need to have some delicious treats on you for training him/her to heel. Investing in a training pouch is your best bet. I recommend the one with a metal hinged pocket that you can slap closed easily. It comes on a belt that you can wear around your waist. These are sold locally at The Kennel Shops, Planet Dog Company Store, Fetch, etc. I'm not fond of the ones with a drawstring closure or those that clip on, as they just don't function well and will mess up your timing of rewards.
Fill your treat pouch with TINY, SOFT rewards. Why? You will be giving lots of rewards to keep your dog in position and moving forward. You don't want to fill them up too quickly, and you want them to be able to chew and swallow each reward quickly and easily. Bits of finely chopped chicken breast, steak, deli meats or cheese work really well. You can also purchase soft treats that can be chopped up into small bits for training. Go with something your dog is sure to work for, as you will be using the food to lure, motivate and reward your dog for the proper behavior.
Another good beginning tool for teaching your dog to stay in the heel position is a wooden spoon. On the spoon end, you can smear peanut butter, cream cheese, liverwurst or Cheeze Whiz.
When beginning training "heel," you need to decide which side of your body you prefer your dog to walk. My service dog, Tonya, was trained to always walk on the LEFT of a human's body, for instance. Now, she prefers to walk to my left at all times. If you choose the LEFT side, the handle/loop at the top of your dog's leash should be on your RIGHT wrist or vice versa if you want your dog to walk on your right side. The leash should come across the FRONT of your body, with the dog standing on the opposite side. This way, the correct hand (left if your dog is walking to the left of you, or right if the dog is walking to the right of you) is free for dispensing treats.
Let's begin. For this article, I'll assume that your dog is on your left side. Just reverse everything if you'll be walking with him/her on your right. For the wooden spoon exercise, you'll have the spoon in your left hand. Every couple of steps, you'll bring the spoon down to your dog's nose level exactly beside your left knee, giving your dog a very brief chance to lick the contents of the spoon. Then, bring the spoon up so your dog can't reach it. Continue walking forward, without stopping, for as many steps as you are able,, dropping the spoon down to your dog's nose level every few steps. If your dog gets out in front of you, STOP immediately, plant your feet and wait for your dog to figure out that NOTHING is going to happen (i.e. no forward movement) until your dog re-engages with you. Eventually, and this may take a few loooong moments, your dog will look back at you. When s/he does this, bring the spoon end close to his/her nose and use it to lure your dog back into heel position beside your knee OR simply turn in the opposite direction and use the spoon to once again lure your dog into the heel position and begin walking again. It's vitally important that you a) keep moving if your dog is attending to you/the spoon and walking beside you and b) stop immediately if s/he gets out in front of you.
If you are skipping the wooden spoon exercise and simply using your treat bag and delicious niblets of food to lure your dog, that's fine. The treat bag should sit in the center of your body so that your dog doesn't get so distracted by it that his/her nose is constantly in the bag. Similarly, you should try to get into a rhythm of walk/grab treat/dispense treat without STOPPING the walking. This can take some time and practice to coordinate, but it's well worth the effort. If you are constantly stopping to open the treat pouch, dig your hand into it, etc., your dog may not understand the "object" of the game, which is walking in heel. So...get your rhythm down and let your dog be your guide in terms of how many steps you take forward between each dispensing of food. ALWAYS treat the dog alongside your left knee, not out in front. Use your hand to guide your dog back into heel position using the scent of the food to bring his nose back into position and THEN dispense the food into his/her mouth.
If your dog is biting your hand harshly out of excitement for the food reward, simply use your thumb to hold the food in the center of your palm and dispense the reward with the flat of your palm, moving your thumb out of the way at the last second, and using your palm to push TOWARD your dog's mouth, thereby keeping him/her in heel and gently reminding him (by the push of the palm back towards his/her mouth) that snarfing and rushing forward to grab the treat is NOT desired and WON'T work.
As you and your dog get the hang of walking in heel, you can then extend the number of steps between rewards. For instance, I used the rhythm of 5 steps between rewards with Tonya for a long, long time before move to 7, 9 and 11 steps between rewards as she became proficient and her understanding of what the "game" was all about increased.
The object of these early training walks is NOT to walk a mile in heel, so make your walks brief and always end on a positive note rather than in frustration. Walking back and forth on the side walk in front of your home, or walking the length of the back yard a time or two is great for these early training walks. It will take time and patience and lots of practice for your dog to "get it" that leash-walking is not a free for all where s/he pulls you all the way around the block, stopping at every tree, lunging at every other dog, squirrel or car that s/he sees.
Let's talk a bit about all of those distractions mentioned above, because those are critical times for training your dog. It's totally understandable and normal for your dog to be tweaked and excited by squirrels, other dogs, bikes, skateboards, etc. while you are walking along. It's also reasonable to expect your dog to be able to behave appropriately despite those exciting distractions. This will take time, patience and many, many repetitions of the appropriate behavior. A few things to consider: If you become tense, stressed and/or anxious when you see an exciting distraction coming your way, those emotions will travel right down the leash and your dog will sense them and respond. The dog's response will most likely NOT be the one you desire. So, stay confident and calm when you see something coming that will cause a "training moment" to happen. If your dog darts out ahead of you toward the distraction and you find yourself with a dog straining on the leash, you can try putting yourself between your dog and the distraction and feeding your dog one treat after another until the distraction passes by. Ideally, you will put your dog in a sit and step on the leash so s/he can't lunge toward the exciting thing. Your dog may be so excited and distracted by the exciting thing that s/he won't eat the treats or pay attention to you. If this happens, it's best to try and change your dog's energy by using a stern voice and saying "uh uh or chit chit" while tapping him/her on the shoulder with your fingers. Continue to block his/her view of the distraction until it passes.
Dealing with exciting distractions will likely be a very challenging part of leash training work. Sometimes, your dog will see or hear or smell the distraction before you are even aware of it and may lunge or run toward it, jerking you along with him/her. If your dog is small enough, stepping on the leash (while keeping the loop around your wrist) is advisable and should be your first line of defense. Blocking your dog's view of the distraction is next. Distracting your dog with the food or rewarding your dog with the food for calm, submissive behavior is good practice.
Your positive, authoritative Pack Leader presence will go a long way toward teaching your dog that YOU are in control and that you expect him/her to stay calm/submissive when distractions occur. Yelling at your dog, jerking him around on the leash, picking him up, etc. are not helpful reactions. Ideally, your goal is for your dog to acknowledge the exciting distraction by staying calm and continuing to walk at your side. Practice, practice and more practice is necessary to achieve this. And...NOT allowing your dog to practice the WRONG behavior over and over again is also necessary. Every time your dog gets to practice going nuts and running toward the other dog/squirrel/person wildly, they learn that THIS works....so they'll keep doing it....and it will become his/her customary habit.
While you are training your dog to walk in heel, do yourself a big favor and choose locations and times where/when you are least likely to encounter the big distractions. Your backyard or the side walk in front of your home may be the best place for those first exercises to take place. Start small....build on small successes....always wear your treat pouch! And, if you are having great difficulty achieving the desired results, don't hesitate to hire a professional trainer to coach you. It's well worth the cost of an hour session!!