I agree with most of the posters. I have a pretty small 20x30 garage and its the cleanest room in the house. It gets very messy, and eventually I get out there and clean it up. I just don't take pictures of my garage when its messy. I tend to take photos right AFTER I have just cleaned it up.
1) Have a nice floor. It brightens the area up and makes it feel like a room, not a garage. Also you think twice about leaving stuff on the floor. You want to be able to see your pretty floor. Thats why I stack all my **** on my workbench.
2) I am notorious for not putting tools away. Because my workbench becomes a pile o tools and ****, I have to pull out the folding tables, spread everything out, and then put it away when it gets too high to keep from falling on the floor. Designate an area for putting stuff that isn't away. Then you only have one pile to clean up, not the whole garage.
3) Get some music out there. Wire in a stereo. Makes time in the garage more pleasant. I used an old surround sound system so I have 5.1 digital surround sound and a TV/DVD setup. A must have.
4) Storage is important. I made my own cabinets, but you can also buy them if you are desperate. I also have lots of clear storage bins in small sizes that I have labeled. Lots of bins are just junk, random screws and bolts, etc. But at least its out of sight.
5) I have a condo I rent out downtown, and I don't rent the garage. I truck everything that is junk to the garage and if I don't use it in a year, I give it to AmVets. That applies to clothing and shoes, old stereo equipment, etc. You could do this in a shed as well, but you get the point.
6) Get the lawn equipment out of the garage. I have one of those rubber-maid plastic storage sheds that are waist height. It holds the trimmer, mower, and gas cans just fine. It also keeps the fumes and fertilizer out of my garage.
7) Have lots of parties and invite people who like garages. That will definitely give you incentive to one-up your friends. Ever notice how car projects never get done until a car show is on the calender next week? Gotta get it done in time. Urgency is a good thing.
8) Keep the wife out of the garage. She put some Christmas decorations in a box in my garage, so I put a 6 foot muffler on her side of the bed. She caught on really fast. She gets to park in the garage, thats more than enough.
9) Is it art, or is it junk? I have a carbon fiber hood hanging on the wall in my living room 10 feet up. I bet you could pass lots of stuff off as art if you hang it on the wall. It was wasted space, and she can't reach it.
10) I still haven't gotten my garage walls painted, so I still have projects to get done. I think I need to have a garage party next month sometime.