Teach Your Dog How To Walk On a Loose Leash 

Treats are pretty useful. Without them it can be difficult to create the dynamic of the dog following you and what you have. It gives them something to focus on, look forward to and cement the rewarded behavior patterns. For contrast, if you try to do this outside by stopping and waiting for it to come to your side, it will not understand that it is a rewarded pattern you are intentionally trying to teach to it and the training will go nowhere. Doing it inside and with treats makes it much easier. The point of the clicker is to instantly signal to the dog the moment the rewarded behavior pattern finishes. It has to happen instantly after the successful execution of the trick or the dog will not know what you are rewarding it for. Some dogs are not motivated by treats.