Having grown up in Wisconsin, where we would see winter days with HIGHs in the single digits and night time lows in the negatives, I am very familiar with the dangers of below freezing temps. Sadly, it does not have to get to those extremes to be dangerous or even deadly. Below 32 degrees is freezing. So here are the four Ps of preparing for freezing temps...
People--Elderly people are especially in danger at these times as they are reluctant to ask for help. Could be as simple as getting their space heater out of storage for them and making sure the space heater is at least a foot away from anything. Check on their pipes and possibly help them pull an extra blanket down from a high shelf. Don't assume your other neighbor will check on them either as they may be thinking the same thing about you!
Pets--They may spend all of their time outdoors but that doesn't change the fact that liquid freezes and there is water as well as blood in their bodies. The have not been conditioned to build a nest or hibernate when the temperatures drop. Bring them in!
Plants--This is the easiest to remedy. Toss an old bed sheet on your plants to keep the frost off them. If you have potted plants pull them together and bring them closer to your home before covering them with a sheet.
Pipes--The headache you get when you realize your pipes have burst is in a category all on its own. You really don't want to take a chance. I few bucks more on your water bill is worth every penny!. But it does not have to be a gusher coming out. Drip just enough water to maintain movement of water. If you don't have to worry about pets or kids getting into chemicals under the sink, open the cabinet doors. The room temp will help keep the pipes warm, too.
Don't forget that just because your home survived the last freeze without having problems that doesn't mean it will again. The last time you got lucky and it may have weakened your pipes for this time...