Not that I've taken my own advice, but there are cookbooks out there that specialize in cooking for one or two. I've bought them, but rarely remember to use them.
I'm taking the radical step of not freezing my leftovers anymore. I have literally just spent the last 5 hours cleaning out my kitchen, refrigerator and freezer, and the amount I waste by "freezing for later" is absurd. I either forget about the leftovers, or I decide I don't feel like eating it anymore, and then the food just gets freezer burned. Then, out of guilt, I still don't throw it out, for like, a year or more! I don't know what the answer is, but for myself I am going to try to stop making full, or even half recipes for "planned leftovers", despite the obvious time-savings, and focus on meals that can be made to size, like stir fry's, stuffed baked potatoes, pasta, etc...