Inquire about his or her training background, years of experience, and areas of expertise. You deserve to have your questions answered, so don't be timid about asking them. Humane training methodology and gentle, effective handling skills.
Reputable trainers are concerned about their dogs' welfare.
They also know that harsh or abusive handling methods are not only unnecessary, but are often counter-productive as well. A genuine love of and devotion to dogs. When you find a trainer with this important quality you'll know it. The joy of living and working with dogs makes this person shine. Extensive behavioral knowledge.