Many of the items you store are in plastic bins. When you buy bins of like size and shape, you can stack them like a tower. And when they are clear, you can get a quick glimpse of the items inside. While you can keep similar bins in one area of your storage unit, when you color code them, your storage items will be easier to locate at a glance.
Color code your bins with pre-made labels of different colors (pick them up at a superstore, home goods or office supply store). Adhere a label to the outside of the bin and keep like-themed bins together. For example, Camping Gear might be blue, Christmas Decor red, Family Heirlooms green, Collectible Magazines black and so on. If a particular box contains fragile items, label it "fragile" as well.
As your storage needs shift, you can easily remove the color-coded labels and substitute them with a different color or add new categories and colors to your unit.