For zippers, I sort them by: metal, plastic, separating, etc. Place them in zip-lock bags, then put all that in a larger plastic tup. Makes it easier to find what I'm looking for.
Buttons: Sorted by color in zip-lock bags, again in a larger plastic tub.
Also, have saved those clear plastic zipper bags that sheets and comforters are sold in. They're great for lace + odds and ends. You can see what's there without digging too much.