Well I have a 3 month old foal. He had some interaction, but not a ton before he was brought to me. Mostly he was put out with momma to do some growing.
I took several weeks of just getting to know my foal, getting him to trust me enough to come up and let me mess with his face and pet him all over. Then I would put a soft cotton rope around his shoulders and just gently encourage him to step forward. All that went really well.
But when the halter came into the picture, he'd get tired of the "game" and back off. So I started feeding he and his mother in a stall together, and while he ate, I'd put the halter over his nose and let him eat through it. Slowly he got used to me doing that, and I was able to put the strap over. He'd pull away some, but with persistence, he'd eat and forget I was there.
Finally he stopped paying attention to me messing with his head while he ate, and I was able to buckle the halter.
It was like magic. It was like after that he just accepted it and didn't care. We're now working on leading forward with the butt rope. =)
But it definitely helped me to isolate them from all the commotion of the big pasture and other horses. In a confined space, I was able to work with him in a space too small for him to really run off, and kept his attention.
Riding: The art of keeping a horse between you and the ground.