So praise and treats strengthen the understanding and willingness of a pup to respond to a given command. Leading and guiding a pup is much more confidence building and educational than using force. If your pup is given the choice between being hauled around on the end of a leash and getting a cookie at the end, or having to pay attention and work for a few minutes then getting that cookie, the pup almost always chooses the lazy way. So let him work for the reward and he will accept it as a job he has do. This is pretty self explanatory.
Puppies have very short attention spans.
Again, working for short periods will be rewarding, too. Hand in hand with working for short periods of time, repetition means doing an exercise for as many times as it takes to get it right, or close to right. Once you get it right, STOP . The pup learns that doing an exercise correctly and quickly is a reward in and of itself, because it doesn't have to keep doing the exercise over. Lack of confidence can be overcome you practicing and working on your own.