1.Shorten your stride length (for now)

In the beginning, don’t just think about “running fast”. Instead you should just try “shorten your stride length” first. If you simply try running “fast”, you may acquire such huge stride that your trailing leg won’t be able to “pull” back under your hip fast enough, and you ended up with your leg lagging behind. Try pull back to the right place (directly under your hip) fast enough while maintaining stride frequency. After your comfortable with high stride frequency and precisely pulling your feet back to the right place, keeping that stride frequency “and” increase the intention of “falling”, you’ll get quicker that way!

2. “Running in the same place” is good!
If you really get the hang of it, you’ll be feeling that you’re running “in the same place!!! Because you’re landing right under your center of gravity!(your hip!)
3. “Fall” from your “pubic bone”!
While you’re trying to increase your intention of “falling”, don’t fall with your belly botton. Falling” from” your pubic bone or between your upper thigh would be better (to avoid getting way too much anterior tilting of pelvis or lumbar lordosis)
4. Exaggerating and feel the difference!
The “drills” aren’t meant to “mimic” “real” running. It’s perfectly normal if the drills don’t look running at all! Do it freely and try exaggerating the movement so your body can feel and learn the specific movement the drills aiming for!
5. Running with your whole body! 
See if your whole body, especially your upper extremities, flows with your legs and pelvis? many people only swing one arm and forget the other side!