Clean It Out - With any organization project, you'll want to remove everything to start fresh. This goes for your shed as well. Toss any old items or trash to declutter your space. If there anything you haven't used or your family has outgrown, now might be the time to donate or sell that item. Though removing everything from your shed might seem counterproductive, it's better to see what you have to store before you create new systems for it.
If the clutter on your property says one unit isn't enough, but your wallet disagrees, supplement your main unit with one of the less expensive, smaller models. There are three main types of such units, all of which go by descriptive names. $Corner sheds$ are made to fit precisely into a corner and run about 3 feet tall by 3 feet wide by 2 feet deep. Meanwhile, either a $vertical shed$ (5 x 3 x 4) or a $horizontal shed$ (3 x 5 x 4) may be just the handy outdoor storage building to fill your need for additional space.