Are you familiar with the TV show "Hoarders"? Well, my mom could be featured on that show. Having been brought up in a house like that, and knowing I have the same DNA, it's a constant battle for me to keep the house organized. So I have gone the other extreme and become a "pitcher". It's SO nice to through stuff away! That leaves me with less things to keep organized. So my suggestion would be to go through and part with the stuff you do not really need. You can sell stuff, or haul it to the dump.
Once you have determined what you want to keep, then you can decide how best to organize your things. Mix & match cabinets (per spongerich's post) are great because you can paint them to match/complement the colors in your garage. I prefer cabinets over open shelving because IMO shelves look cluttered (even with totes). But go with what works for you.
Dave, do you have any pics to share?