1) Maintain your car properly. I don't know that this person did or did not do so.

2) Have a kit in your car, reachable by the driver, consisting of at least appropriate outerwear for the conditions plus at least a Heatsheets or similar blanket. My kit is rather more capable than that.

3) Have a plan. I would be unwilling to use up the car's battery power before escaping.

4) Execute on the plan.

5) Learn from others. In my case, I'm not certain I could get to the shovel in the trunk of my car from inside the cabin. I'll spend some time this week figuring that out.