I use a clicker to train my dogs and my clients' dogs because a clicker is the most effective way to communicate with a dog or almost any other animal that can hear. The "click" tells a dog that a treat is coming. The clicker bridges the behavior with the consequence. Now, this isn't for the remainder of the dog's life. This is ONLY to teach the dog a NEW behavior. Once the behavior is learned, you can use a word marker like Yes!, or Good!, or Yep!. I like to use one syllable words because it's easier to give the dog a cue then mark with a short word.
To use the clicker you press the metal spring piece in the middle of the box. Every time you click the clicker you must deliver the treat so you keep the meaning strong to the dog. If you sometimes forget to give a treat after clicking the dog will not think click = treat. If that happens, you won't be able to teach the dog new behaviors and you will notice if that connection to the dog is fading because you will click the clicker and the dog will not look up at you for the treat. If you click and your dog snaps their head to you like, "Hey, where's my treat?" then you know your association with the clicker and the treat is strong to the dog. Therefore, you have a strong form of communicating to the dog you get better responses from the dog, a.k.a. your dog will "listen" better if it knows what exactly you want him/her to do.
There are different types of clickers. I use a louder clicker that dons my awesome logo and slogan (Happy dogs through pawsitive training) if you want one click here
I use a louder clicker because when I am out in public in a crowded place I like for my clicker to stand out to the dog. The quieter clickers tend to get overlooked when a dog is heavily distracted and is just starting out in training.
Don't use the clicker as a recall or to get your dog's attention! If your dog runs far away from you and you use it to get their attention and it actually works and the dog comes to you, you MUST heavily heavily reinforce that recall and start clicking and treating 10 times in a row so the dog forgets that running away from you earned the initial click and treat.
Don't telegraph the click. In other words, don't use the clicker like a remote. Hold the clicker behind you instead along with your treat/target hand.
Your timing is everything when it comes to marking a behavior. If your dog looks at you and then 2 seconds later you click your dog is not going to understand that click (mark) was for that look 2 seconds ago. Your dog is going to think that click is for whatever behavior they were doing at the instant you clicked the clicker. See, the clicker is so precise that you have to click it at the very instant the dog is doing the behavior or you will be marking a different behavior. So, if a dog is doing a sit, you must click make it look like the dog made the click happen by touching it's butt to the floor. Or, if you are doing targeting, you must make it look like your dog's nose made the click happen when it touched your hand.
The clicker can be your best friend if used correctly and your worst enememy if your timing is off. Hold it behind your back and never click that clicker without delivering a treat!!!!