TIP #1: DESENSITIZATION & COUNTER-CONDITIONING
What is it? Desensitization and counter-conditioning (DS & CC) are the processes of changing a dog’s association with an object, animal, or person from something scary to something safe. While the two techniques are different, they are usually used together to optimize the speed and degree of resolution of a behavior problem. Desensitization works by exposing the dog to the scary thing a little at a time and always at a level with which she is comfortable. In counter-conditioning, the animal is taught to associate a stimulus that previously induced fear with a pleasant experience so that the undesired response is replace by a desired one.
(From your perspective a stroller or a man with sunglasses may not seem scary at all, but to your dog anything strange and unfamiliar can be frightening. Fear is not necessarily logical.)
TIP #2: FADING FOOD REINFORCEMENT
Once your dog knows a behavior well, and can perform it in many locations and with many distractions, you can fade the use of your marker signal and rewards. In other words, you don't need to click and treat every time your dog sits for you. However, it's also important to pay off every now and then to keep your dog in the game and gambling. "This time might be the time the reward happens, so I'm going to keep doing what I'm doing, just in case."
- excerpted from Chill Out Fido!
Jeff Dentler, CPDT-KA, IAABC-ADT, FFCP, CTDI