First of all, I notice that you are in Houston. Converting a garage to use to sew in Houston would be a considerable undertaking because of the need for air conditioning and insulation not only because of the heat but to keep everything from getting damp due to humidity. We have a gas heater in our garage but no air conditioning and even though it's shaded, it's hotter than anything out there in the summer.
I keep my smaller amounts of fabric in boxes on the walls above eye level so that I can have tables for my sewing machines and work space under them. That way the storage isn't taking up floor space. I'm fortunate to have a large sewing room with lots of closet space that I utilize for larger cuts of fabrics and anything else I want to stash out of sight.