Om is right on about eating. I sleep cold and have a +12F rated bag. When I was in Yosemite (7K and +15F) and woke up cold, half a Clif Bar or some chocolate would do the trick. Seems trivial, but made all the difference. As already mentioned, wear a hat like a Turtlefur beanie or a balaclava if you can stand one (I like them during the day, not so much at night), light gloves and socks. I also tossed my parka over my bag, that helped quite a bit.

I was using two pads-a Ridgerest closed cell foam pad under a Thermorest, both are full length.