Find the appropriate kind and size of box for what you want to store. Clothing, holiday decorations and wrapping paper, for example, can be stored in a traditional box. Other items, such as photographs, slides, old newspapers and the like are preserved better in a box suited for them specifically. These kinds of boxes can be found in stores that sell archival supplies.
Label each storage box by writing the contents of the box onto a note card with a marker. Use a different-colored marker for different types of items so you can find them easily -- yellow for clothing, green for toys, and so on. Tape the note card to the front of the box.
Decide on how you want to organize the boxes. You can do it alphabetically, by type of items or by size of box.
Arrange the boxes following your organizational strategy and place them so that each label faces out and is easy to read.