Some basic freezer knowledge will help you better preserve food.
To help cold air circulate, keep food away from freezer vents. For more efficiency and to maintain colder temps, vacuum filters and coils of your refrigerator/freezer periodically (unplug your fridge before doing so).
The more quickly fruits and vegetables are frozen, the less they suffer when defrosted. Clearing shelf space will maximize airflow for a quicker freeze. Increase shelf space with portable wire cabinet shelving.
A survey of test kitchen staff's home freezers showed temps ranged from 5 degrees to -10 degrees (0 degrees or below is optimal). Make sure your freezer is at the coldest possible setting (unlike your fridge, where the coldest setting is normally too cold).
The Coldest Spot
The rear center is the coldest spot in most freezers, so place produce there.