We have several large freezers and over the years, we've discovered that the best way to avoid food spoilage and having items get lost in the shuffle is to separate them using tote tubs.
Using the totes makes this very easy to organize your food by date as well as type.
Using the totes makes it very simple to see which items are running low and need replenishment without having to keep lists on the freezer. To get the most out of the space, freeze items flat (such as soups, pie fillings, etc) and then, once they are completely frozen stand them up in the the individual tote tubs.
Having worked in a restaurant, we follow the FIFO rule, which is First In, First Out. Essentially what the means is- you use things up in the order that you purchase them. If you have frozen chicken in your freezer and you buy more, you place it BEHIND the chicken already there- so that the chicken you purchased first is used first. This way, you're not ending up with freezer-burnt food that has lost quality and nutrients.
The containers used here were purchased at Lowes in the storage/organization department for about $2-3 each. I prefer the heavy duty black plastic ones that are meant for garages because they dip in the front and make it easy to grab items quickly. The other containers are clear plastic rubbermaid tubs that I purchased at walmart for $2-3. They slide out easily and work great. You can fit 2 containers per shelf and still have room between them for loaves of bread, ice cream, etc.
I prefer this method over the "Make a list of the Freezer Contents and cross it out as you go" Method- because it seems that I was the only person in the household to ever pay attention & Cross things out! It also makes it simple to "eyeball" what items you're running low on. The next time you grab a package of chicken or pork (etc) you can see quickly whether you have plenty or need to add it to the grocery list.
How do you organize your freezer? We'd love to see your tips as well . . .