Get a dollar store white-board w/magnet & marker to stick to outside of freezer. Keep a list on what you have. How often have you over-bought or thrown out food bc you don't use or know what's in there? This has saved me time and money. Also, mark down when you froze it or for pre-packaged goods, their expiration date, esp. if stuff tends to hang around in your freezer. Works for the frig, too!
I also keep a grocery lister on there, to write down what I use up or need.