barefoot or flatter soled shoes is fine....if you have the ankle flexibility... try different heel heights to find the most comfortable position...you can progress it back to floor depth if you end up needing more heel height at first.
Doing some strict goblet squats or super-light overhead squats to a slightly-deeper-than-usual depth as a warm-up/stretch will help you groove the nee discipline. The weight should not be distracting...just enough so you don't forget your spine position. I found one of those held at the bottom for 5-10 seconds at a time, while keeping good form, was a big help...
"You must have a very strong reason for doing an exercise. If you don't, scrap it and move on." -Jim Wendler