Any highly valued object such as a treat or toy may be used as a lure, which the dog will follow with her eyes and nose.
Moving the lure in specific ways entices the dog to move her nose, head and entire body in specific ways.
In fact, by learning the art of manipulating various lures, it is possible to teach the dog to assume virtually any body position and perform any action.
Once you have control over the expression of the dog's behavior and can elicit any body position or behavior at will, you can easily teach the dog to perform on request.
Tell your dog what you want her to do, use a lure to entice her to respond correctly, then profusely praise and maybe reward her once she performs the desired action.
For example, verbally request "Tiny, sit!" while you move a squeaky toy upwards and backwards over the dog's muzzle (lure movement and hand signal), smile knowingly as she looks up (to follow the lure) and sits down (as a result of canine anatomical engineering), then praise her to distraction like "Good Tiny!" Squeak the toy, offer a training treat and give your dog and yourself a pat on the back.
Being able to elicit desired responses over and over enables the owner to reward the dog over and over.
Consequently, the dog begins to think training is fun.
For example, the more the dog is rewarded for sitting, the more she enjoys sitting.
Eventually the dog comes to realize that, whereas most sitting is appreciated, sitting immediately upon request usually prompts especially enthusiastic praise and a slew of high level rewards.
The dog begins to sit on cue much of the time, showing that she is starting to grasp the meaning of the owner's verbal request and hand signal.