Start at empty
You've heard it before: Why keep what you don't use? Piece by piece, take everything out of your closet (clothes, shoes, everything), separating into two piles: things you wear (to return to the closet), and things you do not wear (to donate). A good rule of thumb is, "Have I worn this in the last 12 months?"
Unify hangers
Chances are you've collected an eclectic mix of plastic, wood, and metal hangers over the years. Remove all plastic and metal dry cleaning hangers (you can return those to the dry cleaner). Invest in a set of wooden hangers and non-slip hangers to streamline your hanging wardrobe. Everything will hang together nicely, and look real nice too.
Pro tip: Do not store clothing in dry cleaning plastic. Remove and dispose of (or recycle) the plastic wrap as soon as possible and let your dry-cleaned clothes air outside before placing them in your closet, if possible.
Colorize
Return clothing to the closet hanging rod, organizing it by color. This is a great way to make finding that one sweater much easier. Plus, who doesn't like a rainbow?
Wrangle those shoes
If you're in the habit of keeping shoe boxes, take a photo (easy: cell phone and a color printer) of each pair and attach images to the respective boxes. Or, buy some clear shoe storage boxes, which take the guesswork out of it all.
Consider a closet system
Maximize your space by installing a closet system. Work with a carpenter to create built-in shelving or consult a local home improvement store (like California Closets, Home Depot, Lowe's, or The Container Store) about their customizable closet systems.
More: Tour this closet to see how zero-waste guru Béa Johnson and her husband Scott share such small space by minimizing their wardrobes.
Put a label on it
Store smaller items (like gloves and scarves) and occasional items (like guest linens) in open baskets. Create labels for quick ID, especially on high shelves.
Double up
Whenever possible—especially in kids' closets where clothing is not long—create two levels of hanging storage. A shelf above the lower level allows additional opportunity for shoe and bin storage.
Get creative
If closet space is tight, keep off-season items elsewhere. If garage, attic, or basement storage isn't an option for clear storage boxes, consider under-bed negative space (like this bed frame with storage drawers), or lidded boxes or baskets above dressers and bureaus.
Keep it where you use it
Not everything belongs in the closet. Everyday items can reside in the entryway. Create a drop zone with coat hooks, and a shoe bench with bin storage for easy access.
Donate the rest
Make your castaways someone else's treasures. Try taking valuable items to a consignment shop; everything else can be dropped of at Goodwill Industries, or your local donation outlet.
Pro tip: Keep a donation box in the house (try the floor of your most spacious closet), so you can toss no-longer-desired items in there at anytime—freeing up valuable space. When the box is full it's time for a donation run.