A good trainer:

• has lots of tools in his or her toolbox, and knows how to use  them well.
   
• strives to learn as much as possible, from as many sources as  possible.
   
• knows there's always more to learn, and keeps him- or herself  up-to-date by attending seminars, workshops and conferences as  often as possible.
   
• has a strong behavioral background.
   
• has an open mind.
   
• does not behave in an arrogant manner (towards their clients or the general public).
   
• has a strong sense of ethics.
   
• doesn't misrepresent himself with bogus or misleading titles and credentials.
   
• loves dogs [If a trainer doesn't love dogs, s/he has no business training them.]
   
• has patience, and understands that anger and abuse (of any  kind) have no place in dog training.
   
• treats their students (both two- and four-legged) with respect and kindness. (Empathy, compassion, kinship and encouragement towards one's students is essential when training dogs.)
   
• has good teaching and handling skills.
   
• has a good sense of humor.
   
• is passionate about living and working with dogs.