The clicker can be a useful training tool. This piece from Advantage Petcare shares some pointers on how to put it to work.
Here's a particularly interesting insight:
Reward every time. In the early stages of training, each click must mean a guaranteed treat. So even if you accidentally click the clicker, give your dog a treat anyway.
Looking to get your dog a clicker? This piece has almost everything you need to know so do give the rest of it a read too.