Hey, there! I taught at Texas A&M for 6 years, and I found that comedy helped me teach them every time. I would stand up on a table or bench in front of the class and start off by explaining that you only need to know 2 things about squatting, deadlifting, bent rows, etc. If you can just remember 2 things, that you will do it properly.
At that point, I would make everyone stand up and prepare them by saying, "I hope none of you are concerned about what other people think, because you are about to feel very silly. Just remember that everyone else around you is going to feel the same way. So, have fun with it.
Then, I would turn sideways and give them a profile view. I always loudly declared, "The first thing to remember is your BUTT!" I'd reach back and slap my glutes, and then I'd stick my butt WAY OUT by tilting my pelvis. At this point, believe me, everyone is starting to smile and a few are laughing. Then, still in this ridiculous pose, I would exclaim, "The next thing to remember is your CHEST!". I'd take my fist, slap by chest, and then stick my chest WAY OUT and UP. So, at this point, I'm still standing upright, profile view, with a SERIOUS arch in my back...butt out and chest high! Again, laughter would ensue, and I would relax.
From there, I would turn to face them and say that it was their turn. Most would smile and look around. Still on top of the table and facing them, I would yell "Butt OUT", slap the butt, and push the butt back. Everyone would do it, and then I would yell "Chest OUT", slap my chest, and stick it out. Everyone does it and looks hilarious. I'd tell them to take their hands and feel their lower back. I'd ask if everyone could feel the tension in those muscles. Of course, everyone can when you're in that position, and then I would let them relax.
(Sorry this is getting long)
From there, we would squat. I would ask them, "What are the two things to remember?" They responded "butt and chest". AS they would say that, I turned to profile view again. I would repeat "Butt first" and start pushing my hips back. Then I would say "chest up" and start descending into a squat. It worked every time. From that point, I would have them do about 5-10 and watch. I'm telling you...rarely would anyone of them do it wrong.
To elaborate on it, I would show the 2 most common mistakes. First, I would descend into a squat (profile view), with my knees way past the front of my toes. It looks ridiculous, and so I'd ask what was wrong and how to fix it. Usually, someone would say something about the butt, but if they didn't, I would just remind them, "what is the first thing to remember?" and they would answer "butt". As they would say it, I would stick my butt WAY back again and be in a great squat position. They would laugh, but they would UNDERSTAND. That is when I would also show the difference between the weight in the heels and the weight in the toes.
The second common mistake would be demonstrated by going down into a squat with my chest and head down. I would ask what the second thing to remember is, and they would say "chest". As they replied, I would lift my chest up. Worked every time.
So, with that in their brain, it was a snap to teach the deadlift. 1) "Bend over and touch the bar with your shins right next to it". 2) "Stick your butt out". 3) "Lift your chest up" BOOM! 95% of the time = Deadlift position...magic!
For the bent row, I would stand straight up holding the bar at the top of the deadlift positon. I'd show them a few times and then explain how to get into position. "What's the first thing to remember?" "The butt". I'd respond with "push your butt BACK". If I saw any of them doing it wrong, it was easy to fix. I'd say "no, you're bending FORWARD. I want you to push your BUTT BACKWARD." 9 times out of 10, that fixed it. Finally, I'd remind them to keep their chest up.
Oversimplified? Heck, yes. Does it work? Dang near EVERY time. For those that don't, they are probably a kinesthetic learner and need touched or placed into position. I've taught over 2000 students these lifts and can't recall someone that didn't finally "get it".
Finally, I have only one more thing to say: this teaching technique will be even more effective and "memorable" coming from a female, for various and obvious reasons. Have fun with it!