"Imagine what the space will look like when it's cleaned out and how nice it will feel to drive into it each time you come home," Smallin suggests. "Hold this image in your head to inspire you."

Carefully carry everything out of the garage and lay it down on the lawn or driveway. "Group things in categories," Smallin says. "All the garden tools together, for instance, or all the sporting goods."

Broom clean the entire space, taking care to get all the leaves that may have blown in and any cobwebs that may have gathered in forgotten places.

Related: Keeping Your Workshop Clean

Cleaning day is a great time to check the condition and usefulness of the items stored in your garage, Smallin points out. Put aside anything that's broken beyond repair or simply not needed anymore.

People in your community may be interested in the things you no longer need. "Consider holding a yard sale on another day, or look into organizations that accept donations of sporting goods and household items."

Related: How To—Hold a Successful Yard Sale

An empty garage lets you see whether you have enough shelving, boxes, and cabinets to neatly store the items you're keeping. A quick trip to a local home improvement store can fill in any gaps. "It's good to get things up off the floor," Smallin says. "Be sure to take advantage of wall space."

Related:  10 Favorite Wall Storage Ideas

When you're returning things to the garage, keep items organized by category—tools, garden equipment, sporting goods and so on. "Things are much easier to find when they're grouped together," Smallin says.

If you are interested in more about garages, consider:

Garage Doors 101

10 "Neat" Garage Storage Solutions

3 Steps to a Successful Garage Makeover