Here's my list, when instructing.
1. Safety. I want the student to remain unscathed, and learn about frequency control while staying out of the prop arc. I want the student's plane out front where he can see it, and I don't want it to get too far away to see, because I want the student's plane to last beyond the instruction period.
2. Control. Yes, the control reversal thing, but I like to see gentle turns, appropriate control movement, and the plane on the desired path.
3. Okay, here's the most common control issue I have with students : applying too much throttle. Taxiing, I correct them when they're taxiing at lift-off speed. They usually don't repeat that one. In the air, at first, I direct them to give it one less or one more click of throttle. Then, when they have a couple of controls mastered, they want to fly fast. I find myself repeatedly advising the student to back off a few clicks on the throttle, to give them time to react. Only rarely have I seen students trying to fly too slowly. I have seen one solo and then repeatedly stall due to making a 45 degree bank while flying just about stall speed. Usually, though, throttle control is an issue, at some time during the training process.
4. Don't ignore the rudder. You can put it off until after some training, but you need to use it for more than steering on takeoff.

Good luck,
Dave Olson