Final answer:
The first thing to recommend is desensitization and teaching an alternate behavior. Providing mental and physical stimulation is important. Positive reinforcement training techniques and a safe space are also recommended.
Step-by-step explanation:
The first thing you should recommend if a client complains that her dog barks at people passing by the front window is to focus on desensitizing the dog to the trigger. This can be done by gradually exposing the dog to the trigger at a distance and rewarding calm behavior. You can also recommend teaching the dog an alternate behavior, such as going to a designated spot and staying calm, whenever someone passes by the window.
Another recommendation would be to provide the dog with mental and physical stimulation to help reduce anxiety and boredom. This can include providing interactive toys, puzzle feeders, and regular exercise.
Lastly, suggest using positive reinforcement training techniques to reward the dog for calm behavior and providing a safe and comfortable space away from the window where the dog can relax.