To train a dog to heel ask your dog to sit in the heel position, not in front or behind. It does not matter which side, but the treat should be in the hand closest to your dog and the lead held loosely in the other. Show your dog the treat and tuck into your body just above their head, this will encourage them to connect with you and follow you with the promise of positive rewards. Once your dog is connected to you and looking at you, take one step so that your dog follows the treat looking at your hand beside you. Treat after one step if they successfully stay at your side. Repeat this five times, teaching the word association ‘heel’ and reward when your dog is at your side.
Communication is also key so ensure that you are using the word heel in a positive, upbeat and fun tone. Now that your dog is connected and staying at your side, then you can start to add distance, increasing one step at a time between treats. If your dog does disconnect and walks in front of you, avoid using the lead to pull them back as this will activate pulling. Instead stop, reconnect, lure them with the treat hand back into position by your side and start again.
Practise this around the home and garden at first around minimal distractions to set your dog up for success. Once they are successfully able to do 20-30 steps start to practise outside on your way home when your dog is relaxed, then in the park and finally you may be able to add the big distraction of excitement on your way to your walks too. It is important to ensure your dog will not always be dependant on the food lure to heel. Once you have a solid fifty steps of heel on walks then start to put your treat in your pouch and not in your hand and reward intermittently. Eventually you will only need to treat occasionally, especially once the behaviour has become habitual.