Assess the clutter.
Start by creating three categories: keep, donate, and toss. As you work your way through the items in the basement, assign each one to a category. If you rarely use a piece, it’s probably a good candidate to donate or toss.
Donate or toss.
Contact local charities and arrange for a pickup of items to donate; put the toss items out with the trash or recycling.
Edit the belongings you’re keeping.
Separate the keep pile into new categories, such as books, sporting goods, etc. Assign each category a location: Books should be stowed in a plastic storage box placed on a high shelf (or in a corner of the attic); sporting equipment might be sent to a bin in the garage.
Give anything that’s not plainly identifiable a clear label. (Tuck a permanent marker and blue painter’s tape in a zippered plastic sandwich bag and have the kit handy for labeling anything and everything.)
Choose the right shelving.
Shelves are critical in the basement, since you’ll need to keep your valuables safe from flooding. Consider installing metal shelving: It’s affordable and easy to assemble, and it withstands heat and humidity better than wood.
Pick plastic storage boxes.
Cardboard boxes, no matter how strong, bend and dent with frequent use—and they’re not much protection from dampness. Instead, choose sturdy plastic containers, which shield their contents better, seal tighter, and are easy to carry or move around on shelves (as long as they aren’t too big).
Hang items to save space.
Use hooks and pegs to create order out of disorder. Consider hanging such items as fire extinguishers, tools, and work gloves.