Assess the clutter.
Start by creating three categories: keep, donate, and toss. As you work your way through the items in the attic, assign each one to a category. If you rarely use a piece, it’s probably a good candidate to either donate or toss.
Donate or toss.
Contact local charities and arrange for a pickup of items you would like to donate; put the toss items out with the trash or recycling.
Edit the belongings you’re keeping.
Winnow the keep pile even further, creating new categories, such as out-of-season clothing, tax returns, etc. Allot each category a location: Tax returns might be assigned to a plastic storage box placed in a corner of the attic; sporting equipment might be sent downstairs to a wall cabinet or 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.
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. Instead, choose sturdy plastic containers, which protect 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 bring order to disorder. Consider hanging fire extinguishers, fishing rods, and anything else you’d like to get off the floor.