Freezer = Friend

Of course, you have many friends, but your freezer should be among your best. Since you will be preparing food primarily for just yourself, you may run into lots of waste. You open a jar of pesto, but only need one scoop. You make some incredible spaghetti sauce, but can't possibly eat it 3 nights in a row. Tossing things out is such a waste of time and money. Instead, keep a stash of Ziplock or Glad plastic ware around and pop fresh leftovers (under three days for most items) straight into the freezer. Labeling is a good idea - just grab a Sharpie and write directly on the container. Name and date is good. You don't want to keep things frozen more than a few months and many foods looks strangely similar when frozen.

P.S. One final note: I am not a huge fan of placing plastic ware in the microwave. Prefer to run the container under warm water and and put frozen item in a nice microwave-safe bowl. Then, press "start".