If you're renting somewhere that gets winter weather, it's worth confirming a few things before you drive off — tire condition matters more in snow than almost any other factor.
Ask specifically whether the vehicle has all-season or winter tires if you're heading into mountain or snow-prone regions — the difference in grip is significant.
Keep the gas tank fuller than you normally would; running low in cold weather increases the risk of fuel line issues and leaves less buffer if you're stuck waiting out a storm.
Pack basics — an ice scraper, blanket, and phone charger — even for short trips. Winter weather changes conditions faster than it does in other seasons.