A smart dog can also be easily distracted! If they have a strong prey drive or are a scenting dog, they are going to tune you out when walking unless you are more exciting than everything else going on.
The first step is to train an ATTENTION CUE. This should be a sound i.e. a kissing noise, whistle or leg tap. Practice in the house first. Toss a treat, use your CUE and say YES and reward when your dog turns towards you. Once you have mastered the attention cue, try it on your walk.
Another great exercise is COME FORE – the how to video is available under Training & Socialization Walking on Leash section. This is a great way to redirect your dog.
A squeaker in your pocket can also redirect your pup to you.