The only time I would smile (or indeed speak to - and that would just be "thank you") at the judge is when after going over my dog they ask me to move, and perhaps again after completing my pattern.
I also believe that going in the ring with a confident & positive attitude ("ok so my dogs the best, who's going to be second) is the best way of 'selling your dog'. After all if you enter the ring with a defeatist attitude and lack confidence it will go straight down the lead to the dog. By the same token I don't believe in over doing it, being flashy and over the top endears you to no-one, least of all the judge.
JMHO
Shaendix, I don't know if you have a Junior Handling Association over in NZ like we do in the UK. These youngsters really are worth watching. They are an object lesson in being inconspicuous, whilst getting the very best from their dog.