This is a video documenting my method for restoring heavily damaged headlights for a Kia Soul. I can't promise you will have the same results, but this is what worked for me.
Links to materials from the video:

Headlight Clear Coat
https://www.amazon.com/gp/product/B01...

Drill Buffing Pads (not the ones I used, but similar):
https://www.amazon.com/CANOPUS-Car-Dr...

▬ Contents of this video ▬▬▬▬▬▬▬▬▬▬

00:00 - Introduction and Explanation
2:58 - 400 Grit Dry Sanding
4:39 - 600 Grit Dry Sanding
6:36 - 1000 Grit Wet Sand
8:47 - 1500 Grit Wet Sand
9:23 - 2000 Grit Wet Sand
10:08 - 3000 Grit Wet Sand (optional)
11:38 - Polishing Compound
14:22 - Polish Results
16:17 - Clear Coat Results