I think for someone who wants to help people and their dogs, is best going along to a few dog clubs of different sorts covering obedience, flyball, agility, trialing (if you can), ringcraft, heelwork to music and to start with just observing a range of instructors. Maybe one club will run KCGC, another will teach “APDT approved methods”, but one thing is for sure – its the best way to experience the diversity of methods that you can use with a dog. Maybe have a look into alternative approaches like t-touch aswell – the more tools that are in your “toolkit” the more rounded and confident you’ll feel.
If you have your own dog, great try out some basic obedience as suebee says majority of pet owners just want their dog to walk nice on a lead, sit, stay, down, recall, and be OK around food / dogs / people. Details of how to do these basic things are posted all over dogboard for free !! 🙂