I don't teach or recommend so-called "purely positive" methods that allow misbehaving pups to continue misbehaving, instead of teaching them which behaviors are and are not allowed. "Purely positive" is fine for teaching tricks and high-level competition exercises, but NOT for teaching the solid good behaviors that all family dogs need to know, and NOT for stopping behavior problems such as barking, jumping, chewing, nipping, chasing, etc.
Just as a child needs a caring parent; an athletic team needs a coach; your puppy needs a leader and a clear social hierarchy. If you do not take up the role of leader, your dog will; and you will end up with an unruly, disobedient dog. Many people try to win their new puppy's love by letting the puppy always have its way. Buckets of affection is a wonderful thing for most puppies, but it must be tempered with respect.
Clicker training, a common form of positive reinforcement, is a simple and effective dog training method. Although it is still fine to train your dog without clicker training, many people find it helpful. With clicker training, you can easily and effectively teach your dog all kinds of basic and advanced commands and tricks. It's fast and easy to learn how to clicker train your dog How Does The Dog Whisperer Potty Train Puppies ?