Say you're sorting out the top shelf in a utility room closet. You've decided that party supplies should live there, but right now, the shelf is a jumble of old floral vases, rejected knick-knacks, extra cleaning supplies and board games. Cleaning supplies go in a box destined for the kitchen. Board games go into another box. Repeat until the shelf is empty.
Shift boxes to their new storage site.
After you've cleared your shelf and wiped it down, deliver the contents of each surviving box to the new site according to your assessment list. Board games go to the family room shelves. Yard sale boxes live along a garage wall waiting for spring and your yard sale. Set a timer and plan your put-away. You have to deal with the cleared items, too, so plan for it.