Emptying the freezer out, consolidating similar items and using containers to reduce the appearance of clutter are the three main steps to organizing food in an upright freezer. This process optimizes the use of space, allowing for easier access to needed items.
Empty the freezer in three different stages (door items, top shelves and bottom shelves), so that food does not thaw while organizing the freezer. Then, find a way to consolidate similar items. For example, four partial bags of frozen strawberries can likely all fit into one or two bags, or even into a gallon storage bag. Grouping similar items together (fruit, vegetables, desserts and so on) makes it easier to hunt for needed foods later on. Containers stacked vertically make use of upright space.