#1. Use them while they are fresh.
#2. Use them as close to their natural form as possible; i.e. spaghetti turned into baked pasta, roast beef shredded into loose meat sandwiches.
This weeks creative use of leftovers has gone something like this: Tuesday I slow cooked a pot roast with potatoes and carrots in the crock pot. I served three adults and two children and put the leftovers in the refrigerator. Today I cut up the leftovers and put them in the crock pot with the addition of packaged brown gravy and a can of corn (use whatever vegetable you have on hand). This meal fed another three adults and two children.
Now, I fed my husband soup so later tonight he is going to be hungry again at which point I will cut up some leftover steak and assemble steak and cheese tortillas for a late night snack.
Other uses for leftover pot roast; beef BBQ sandwiches or shepherds pie.