Looks like good idea. I wish I had some advice how to do it because I have a 40x48 that is a disaster! I have been saving things here and there in case I need it, then when I do need it I can't find it. I am hoping for a free weekend to throw a lot of stuff.
My first advice... learn to love e-bay. Once that piece of miscellaneous junk that I knew had value could be turned into money, cleaning out was much less traumatic. Ditto for Craig's List. A yard sale was a real big motivator for me too. I had one last weekend. I cleaned out a ton of space and ended up with about $500 from stuff that came out of my shop. (A new table saw followed me home yesterday.)
My garage is roughly 20' X 25'. There's is an art and science to making a small space work. Maximize the use of wall space. Build a lot of heavy duty shelves. Make tools and equipment portable. Watch Craig's list or the want ads for old cabinets. Lazy suzan cabinets are the best use of corners in my opinion. Learn to love peg board, and think 3 dimensionally. Hang your stuff like they do in stores. Put all of your hammers in a row rather than side by side, etc.
You have to organize both your time and your space. I can't keep multiple projects going at the same time. I've started the tradition of beginning every weeknight project by putting a soda in the deep freeze. When I'm done working for the night, the soda is just cold enough. I break out the soda and spend the time I'm drinking to clean up my tools and stuff for the night. (I'm sure you beer drinkers could improvise.) It's worked well for me so far.
I'm a big auction nut. I will have to plan time after I bring home a truck load of treasures to organize and sort out what I'll keep, what I'll sell, and what I'll donate. I have a whole corner of the shop now dedicated to the transient auction stuff that I'm going to sell.
The first step is to get started. I've taken about two weeks of nights and weekends to casually go through the years of junk. I'm probably about half done. I need to do another good round of e-bay selling, and I'll probably start collecting another pile of stuff for a yard sale in the spring.