Puppy pulls while walking

Training beagles to heel is HARD!!!! Most of the time I use the stretchy retractable leashes, so they can sniff when they want to, but I can still have a lot of control if I need it. I have had limited success with training them to heel, but I haven't tried classes. That worked well with an impossible Alaskan Malamute (who also love to pull and are about 2x the size of a beagle) I had ages ago, I actually won a blue ribbon on him in the show ring. I would like to try Cesar Milan's collar (the Dog Whisperer).