1. A warm body stays warm. In winter backpacking, before bed, I'll put on the snowshoes and hike down the trail for about 15 minutes to get the circulation going. No cold hands or feet. Never go to bed cold.
2. Cover up your head. Use a knit cap or a balaclava
3. Empty that bladder! No need to heat that all night and will let you sleep longer
5. Hot water bottle if necessary
6. Down booties......they work!
This might be a little extreme for your temps where you are, but let's you get an idea of what is needed if it were to get really cold. I could see you using a few of these tips.