While I am by no means a dog trainer and am still learning about the Havi breed, we are also teaching our two little ones this so we can relate and will share what I am doing. I happen to feel that a dog should be allowed to be a dog though, and jumping up is one way they greet each other and play. But, they need to learn to control this behavior because, for humans, there are definitely times we do not want possibly diry little feet on us!
First, I can see that it depends in part on the personality of the puppy. From a dog breeder's perspective, it also depends on if this jumping up was encouraged in any way (even without realizing it!) at the breeders home. In living with a small breed now for all of 5 months, I think it might be a wee bit more ingrained in them since they are small and want to make themselves higher? Not sure about that, it's just a theory at this point.
Anyway, our Shiloh is not as inclined to jump up, whereas Lizzie is all about jumping! For both, I have found saying "paws off" works better than just "off". Again, I am not a dog trainer, but with our working breed the English Shepherd, we have learned to ask for the behavior you are also trying to avoid. So, for the Havi's we teach "paws on" and "paws off". "Paws on" helps in picking them up onto my lap for snuggles. And I feel it helps their brain make a connection somehow between off and on.
Make sense? Probably not. I really have no idea but just try to think like a dog, get inside their smart little brains, and hope I can stay one step ahead. LOL