You can build garage shelves especially for your space if the pre-made shelves you find aren't what you need, or if you simply prefer to do it yourself.
Step 1 - Determine Materials Needed
First, you must figure out what you need and purchase the correct materials. If you have cinder block or brick walls in your garage you'll need to mount studs to the wall with concrete screws. Measure and calculate where you want your shelves and how long they should be.
Step 2 - Gather the Materials
Take your measurements to your local home improvement store or lumber yard and have the lumber cut to the correct size. While you're there, purchase the mounting hardware you'll need. You can purchase bracket kits if your shelves will be stationary, or a rail/track system for mounting your shelves if you want to be able to move them later. Purchase a minimum of two brackets per shelf. For long shelves, a third or even a fourth bracket equally spaced across the shelf offers extra stability.
Step 3 - Finishing the Job
Mount the brackets or the rail system and hang your shelves.