Freeze as You Mean to Go On
If you are going to start freezing food, it’s a really good idea to empty out your freezer first. Ideally you should clear it down by eating the contents and then defrosting and cleaning it.
To make sure that it is the right temperature order a freezer thermometer. It should be -18 °C to freeze your food effectively. It's worth having one for your fridge too which should be between 1 - 5 °C.
I really recommend not skipping this step as it will help your freezer to run more efficiently (plus you can fit more in if it's not full of frost!).
Also, your freezer works better (and more cheaply) when it is full (but not over-filled), so it is better to go through the pain of defrosting it and then you can set to filling it up with a fabulous Freezer Stash. Generally speaking it will then only need defrosting once a year, or when the ice build up is over 1/4 inch thick.
If you don't have time to do this just yet, don't let this stop you from dabbling; it's easy to try out The Full Freezer Method even if your freezer is a little unloved. Just freeze small portions of ingredients and use them regularly.
Remember when using your Freezer Stash not to leave the freezer door open as this will allow the warm air in and your freezer will get frosty fast! I usually take out the bags that I need, put the ingredients into bowls ready to cook (I usually take meat and fish out first to defrost in cold water) and then return the bags to my freezer.