Sort before you store
Separate the things you reach for every day from seasonal clothing, spare bedding and items you no longer need. Moving clutter into another container does not create more space.
Measure the full opening
For under-bed storage, measure the lowest clearance, the available depth and the gap the bag must pass through. For drawers, measure the inside base and the height below the drawer above. Leave room to lift, slide or open the container.
Choose access over capacity
A smaller container you can reach is often easier to use than a large one you cannot remove. Keep frequently used items near the front and label the things you put away.
Try the layout first
Use an existing box or a paper footprint to see how the arrangement feels. Check doorways, drawers and access routes before buying anything. Follow product instructions and avoid overfilling containers.