I've had to tame 4 PMU's not handled and full of fear. I like cowgirljenn's method best and that's pretty much what I did. Slow desentization method.
First bucket training: feeding via bucket every day with graduated touching. Holding bucket standing at first; touching forehead, nose, cheeks then ears then throat then neck & so on.
Second: hold halter, put it in bucket, hang from your arm/hand, touch face w/it, let it become part of feeding episode. Make a not scary thing. Drape it on them over neck/back
Third: put rope around neck/ears/ face; tug & move it around, hang it on poll while they eat.
4th. : using a feeding halter; make it so they have to put nose thru to eat; then eventually slip over ears, lots of praise of course, make it not scary, slow but steady
If they wanna run away or get scared; let them run or move away. Stand still and let them return to eat. I did most of my taming sitting in a lawnchair in their run in shed. I was less scary sitting at their tlevel. Mine started this about 6 mos old. One took 2 mos, one 3 mos. It's the trust that must be earned and the fear reactions will lessen until their evasions just become a head movement. And yours has to un-learn his built in run reaction.
Don't want them associating haltering w/something painful or scary. But with pleasurable things.
Years later mine will follow me anywhere if Iask them without leading ESPECIALLY if I'm carrying a bucket!!! And I always try to reward them if they allow catching/haltering. One took almost a year before I could totally earn her trust and touch her/work w/halter training. She preferred me touching/rubbing/sratching her HIND end first. So I did! She ADORES a good tail scratch & butt rubbing. So now i have a 16h'-ish draft crosss who walks up to you, past you and backs her rear towards you and turns and looks at you to scratch please!!
I have not been kicked except when surprising them. I take the hint when they threaten. I back off some then start again. I needed to become their benevolent herd mom. Their "preferred associate"!!
Mine was an emaciated rescue so I suppose I had an advantage because if I had food I was the center of his universe, but I was first able to get the halter on by having food in one hand and using it to get him to put his nose through the halter. Mine was never skittish about pressure behind his ears like someone else mentioned. Food is how we became friends. If I had food I could get him to eat from him hand... otherwise he would scoot away from me or kick at me if cornered. When they are little and don't know humans, kicking is instinctive to protect themselves from the perceived threat. I don't think reprimanding is the way to go. A smack would only confirm that the human is a scary thing. Mine would let him rub his head and neck, and gradually I could touch further and further back, but overall he seemed to catch on quickly. I was careful not to push him beyond his comfort zone, make every interaction a pleasant one. 10 years later I still have this horse, and we have a bond that I will probably never have with another horse again.
And if you're smart, you'll attach about 4 ft of heavy cotton rope to the halter before you start and Leave It Attached, until you can get the horse to come to you reliably. The at least once the halter is on, you have a little advantage.
Also, if you have a steady eddie, older horse around, halter it first, use it as a "hey, this isn't so bad, you get love and treats" ploy.
I was tasked one summer with halter breaking two, 2 year old, untouched Standardbred fillies. They were in a 5 acre field with running water and lush grass. It took me a week to get near them, another week to get them to follow me (sweet feed is your friend) an another week to get them to go into a stall for their food.
I made the mistake the first stall day of putting them in stalls where they couldn't see each other. They went completely nuts and nearly climbed out, once I put them across from each other, it went much better.
Wear heavy gloves and make sure you don't put your hand anywhere it shouldn't be and if it all goes south then just let go and live to fight another day.
I got them come here, halter, lead and follow me broke. I opted out of pick your feet up, get in the trailer and wear this harness stuff, I let the Amish boys sort that out, these fillies were studdy and big.
Really well bred, the owners of the farm had died, they'd been kicked out back as yearlings and they just sort of forgot them. Some neighbor threw them winter hay, eventually the owner's son got ahold of someone at the track, then got me. They went on and had fairly decent racing careers, but they were never really easy to handle.