First of all, I train with a leash first, and then train without the leash. If I call FRONT, and back up, that means the dog must come to the front of me and sit close enough so I can pet her head and hold the collar -- I do not, but I can.
then I say FINISH, and she will swing over to my left side and sit in the heel position. Or I will say AROUND, and she will go behind me and sit in the heel position. Then I say Heel, and lead off with a half-step with my left foot. If I do not want them to SIT in the heel position, I say HEEL and start moving before they are all the way around in position.
On walks, we heel some of the time, always across streets, the rest of the time, I give them some lead, and so long as they do not pull me, I let them sniff and be dogs.
ETA: If we are ready and working off-lead, they need to be in heel position, sitting when I stop, heeling when I am going, all the time.
Heidi Ho, Odie
Joy-Joy, Bear Cub, Hepsi-Pepsi
Cujo2, Karma Chameleon
Ramona the Pest, Kojak -- who loves you baby?
Tiny Tinnie, Susie's Uzzi, Kaiah -- The Baby Monster.