My yearling decided he wanted to evade the bridle, he knows to drop his head for poll pressure but decided to ignore it when he saw the bridle (snaffle) coming. He's already 15 hands as a yearling and wanted to nip this in the bud so I cheated. I used a long lead rope, went from the bottom halter ring, through his front legs and around the barrel. Asked him nicely to drop his head, but had his head tied so if he raised beyond level he hit the lead. I put the bridle on matter of factly, went on with our lesson. A week of this and no more raising his head. Obviously this only works when you leave your halter on underneath, but now he gets that he isn't allowed to raise his head, so no need for the halter anymore. Like someone else said, always respect their teeth and head, be careful when slipping the headstall on, and praise for good behaviour. Just don't tippytoe around it our make it a big deal.
There is no passion to be found playing small - in settling for a life that is less than the one you are capable of living. - Nelson Mandela