Step 8: Sleep Tight.
Crawl into your cozy bag and drift to sleep in the great outdoors. Keep an eye out for signs of trouble, though--when you first get in, you'll be warm, but when your body becomes sedentary it's likely to cool down a bit before your sleeping bag warms up. If you keep getting colder, you may need to add more clothes, but don't constrict yourself. Place your hands in your armpits to keep them warm. If you're shivering and stop but are still cold, congratulations! You've got hypothermia! Get moving. Make yourself more tea and a fresh hot water bottle. Use your head. Sleeping in the cold doesn't have to be dangerous, but it's always risky. Know how to deal with these situations.
Of course, if you've followed these instructions and aren't at a polar research station, that's not likely to happen. Most likely you'll awake in the morning, refreshed, ready for a new day, and contemplating whether or not you'll survive the shock of transition from the warmth of your bag to the frigid hellscape of the tent.
I hope this has been useful. Good luck!