Understand the market they are selling into. Decide how to get the right message to the right people. What You Are Selling You are selling an awareness and motivation message. Awareness is obvious. You should provide a clear and forceful message that your pet is missing.
Motivation is more subtle.
For instance, someone might have your pet, know your looking for it, but lacks the motivation to return it. Or someone may be aware that his neighbor has your pet, but lacks the motivation to confront the issue. Someone may even make the connection between a pet on the street and the one on your poster, but sees no reason to remember where your poster was. Very few people will interrupt their routines and schedules unless they are motivated to stop and help. Most searches fail because few people know about your lost pet and fewer are motivated to do anything about it.