If I were training someone today to switch from severe heelstrike to forefoot running, I would do the following. (I would only do this for runners who were getting injured due to heel striking or runners who wanted to get faster. The typical recreational runner who is fine with 8-15 minute per mile pace doesn't need to change.)
1. Switch to a low heel-to-toe drop shoe with good forefoot cushioning.
2. Get to a track. Run barefoot on the infield for a few 50m strides.
3. Immediately put on shoes and run with the same barefoot form on the track.
4. Step off the track, do a couple of easy short strides barefoot. Put on shoes again, and mimic that form on the track.
5. Be patient. It's easy to sprain the plantar fascia by doing too much barefoot running too soon.
I'd also have them do drills to get as much of the arm swing behind the torso as possible. I've described this in other posts as "elbows back" where the runner tries to get the upper arm parallel to the ground on the backswing. Not everyone can do this, but it's a drill to come close. The next part of the drill is to keep the hands close to the chest on the front swing. I'd train them to lightly touch the pectoral muscle with the back of the thumb just by the armpit. Exact placement is unnecessary. The purpose is to keep the hands close to the body on the front swing. The combined effect is to create a very slight forward lean by keeping some of the weight of the arms behind the torso throughout most of the running motion, which in turn helps with forefoot strike. In contrast, extreme heelstrikers tend to run more vertically with their hands further out in front of their chests on the front swing.