A lot of the storage and organizing hacks I write about are geared toward those living in a small space, but before I moved to New York City and began inhabiting miniature apartments, I was living comfortably in the Midwest, where houses are cheap and big—but hard to declutter and organize in their own way.
My parents' house had a room called the storage room, which I never realized I would one day consider a nostalgic luxury. That room held seasonal decorations, old furniture, mementos, and a big freezer full of extra food in case we got snowed in. (That's part of the reason it's so cheap to live out there, by the way.) My parents kept this thing in tip-top organizational shape, making it a super-useful space, but if it had fallen into disorder it would have become a major burden instead.
Whether you have a dedicated storage room, an attic, a space in the garage, or a storage unit, you need to keep it organized so when you do have occasion to use the things within it, you actually know where they are.
Shelves and bins
First, you need shelves. You need a lot of shelves and, ideally, they should be big. When you're organizing, it's important to remember that everything you own needs to have a designated spot for storage, so shelves on their own aren't ideal, since they can get cluttered themselves. However, they are perfect for holding containers, which is what you'll need after you get the shelves situated. My storage room had shelves built into the walls all the way around the perimeter, but more importantly, they were all uniformly and evenly spaced. Fill a wall with sturdy shelving and try to make sure all the units are the same so it's relatively seamless.
As mentioned, you're going to need storage boxes. I recommend using sturdy, plastic bins instead of cardboard, since basements, attics, garages, and unfinished rooms can get a little damp. Again, these should be uniform so all the boxes can stack nicely on the shelves and on top of each other. You can get a six pack of 54-quart clear bins for $89.99, but avoid getting the kind with wheels if you're going to put them on the shelf. That's just asking for a catastrophe.
On the other hand, wheels are handy for things like Christmas decorations, so you can easily take the entire bin out into your home when you're decorating for the season. A solid option in situations like that is this set of three stacking bins where the bottom one has wheels.
How to actually organize the storage room
My recommendations for what kinds of shelves and bins you need will only take you so far. You also need to declutter and organize the space. If you need some motivation, consider the concept of Swedish death cleaning: Imagine what a burden this room is going to be for your descendants when you die. It's macabre, but it works.
As for the best cleaning and decluttering technique to follow in a room overflowing with old stuff, I recommend pro organizer Andrew Mellen's Organizational Triangle, which follows three basic principles: Every item needs a home, keep like with like, and use a something-in, something-out approach. Start by removing everything from the space. You can do this when you're ready to start using your new shelving and bins. Sort through all the stuff, categorizing it into piles based on similarities, but also being judicious about throwing away anything you don't need to hold onto anymore. For example, Thanksgiving decorations go in one pile, barbecue tools go in another, bike accessories in another, etc. If you have any duplicates, get rid of all but one right away. Then, put every distinct pile into its own bin. Again, everything needs a home—a bin—and everything should be stored with similar items, so you know exactly where to look for whatever you need when you need it.
Finally, you're going to need a labeling system. Even if you're using clear bins, it can be hard to figure out what's in there. Grab a big label maker, like the Brother QL-600 ($79.99), which supports labels up to 2.4 inches in size, and use it to clearly define what's in each box.
For an extra decluttering boost, any time you open one of the bins, go through it using the decluttering method of your choice, gradually paring down the amount of stuff you actually keep in there so you can stay on top of your organization even more.