Why do I recommend you use a clicker?
On the other hand:
Before you can use the clicker for training you need to teach your dog what the clicker means to him. This is known as "Loading” or “Charging” the clicker.
To load the clicker, simply click the clicker and give your dog a treat. If you repeat this frequently, your dog will soon learn to associate the click with a reward. Don't worry if your dog is initially startled by the click - once he or she realises treats come after the click, (s)he will adjust to the noise.
You will need at least a handful of treats or your dogs regular food (dinner is perfect), since you will be practicing this over and over.
Repeat this three times a day for a week. Vary the amount of time that you hold the treat in your hand before using the clicker so that your dog does not begin to expect when the treat will come.
If your dog wants to sniff and try to get at the treat, keep your hand closed and wait until he loses interest in the treat before clicking again.
I also recommend you download and have a read of this excellent handout about Clicker Training!