Like anything worth doing, patience and work is required. It took me 6 months to make the switch, but it was worth it. I run in flat sandals. Check points: Can you stand barefoot with knees straight and touch your toes? Now put a 2" thick book under the balls of your feet - can you still touch your toes? If not, work on flexibility with toes straight ahead, turned out, and turned in (using the book).
As I said, I dont' run barefoot, but in flat sandals - Nike Rayong I, and Nike Straprunners. Rayong I's are great, with a nice flexible sole, but are no longer made, so I am looking for replacements. I paid $80 for 4 pairs. I taped the velcro straps so they would hold on sharp turns. Rayong II's have a forefoot design defect on the edge. Except in deep snow, I run through all 4 seasons in sandals, wearing Wright Socks medium weight spring thru early fall, and Smartwool medium-weight socks from late fall thru early spring. The sandals only weigh about 5.5 ounces.
There is something magical about running on pine needles barefoot style. Find yourself a pine needle trail - I don't care if it's only 50 yards long - and run on it. If it has a slight 1-3% uphill slope, you will find your forefeet easier. Some areas have old pine plantations planted in even rows. Loblolly Pines are great, because the branches are high up. The spring from the needles combined with your flexible achilles is great. Broadleaf trails are great too, but pine is the BEST!
To develop barefoot strength, hop on a treadmill. Keep it s-l-o-w, no more than 6 mph. Hard to find your forefeet on the flat, especially in heeled shoes. Raise the incline to 3%. You begin to find your forefeet. Now go up to 4.5%. Bingo! Now you can feel it. Light steps. No pounding. Footsteps like brush strokes. A little spinal engine twist. Walk some. Try it again. Take it back to the pine trails.
I run 4:21 pace trail sprints thru trees using this technique, and 5:20 pace over rolling, twisting, single-track trails for 3 miles. I'm 50.
Have fun!