I love the 80% idea. It is a realistic bar to shoot for. I like the concept of leaving something in the tank for really necessary times. It's like having an extra gear, a little boost in reserves. Okay, okay, I admit in my slothlike ways that my 80% is like a lot of people's 20%. Also, hockey is not a good metaphor for me. I'm more like a sprinter or maybe a drag racer. I go flat out for little bursts of time and then rest (or dismantle myself for cleaning), but I'm sure it averages out to around 80%.
The other way I manage is by trying to keep the Big Idea in mind. I think I've become a better teacher by going for one or two ideas and going deeper instead of bogging myself down with the minutiae (which is REALLY easy to do). In any project (including my own), I try to think about what is the main thing I want to accomplish out of all of this.
Both the 80% guide and the Big Idea concept are applicable to classroom design. Whenever I'm helping someone figure out what to do with their classroom, I apply the Big Idea question, "What do you want your classroom to do or say?" It really helps to cut out all the distracting non-information and useless features of a classroom. (If you want a tranquil, harmonious classroom, you might want to take down the Call of Duty posters.) The 80% guide is great during the implementation phase. The teachers I work with are always very enthusiastic, but they often bite off more than they can chew. They get rid of all of their desks at the start because they like the uncluttered look it gives. But by jumping in so drastically, they either get overwhelmed and can't continue (though they still have plenty of energy to curse me) or they implement too quickly and can't adjust to unforeseen factors: "Sure, the classroom is uncluttered with desks, but all of the students' materials are spread all over the floor because we don't have a place to store their stuff," or "We have lots of room to dance, but painting and writing is an issue with no desks."
I got lucky. When I implemented the risers, because I was so cheap and inept with carpentry, I only had enough materials and time to create one set of risers. This great restrictive accident let me implement the risers slowly and the first set turned out to be a great prototype. I was able to see the mistakes I had made and the changes I needed to make for future incarnations. If I had jumped in and made all of the risers in one go, I wouldn't have learned that I needed to make the lower ones wider (to allow for kids' backsides and feet to co-exist on the same surface) or I would have learned it too late after I already made all of them. In Matthew Mays' book In Pursuit of Elegance, he talks about how the best designs have something missing. Gradual implementation with room for customization is key to this kind of prototyping.
My advice to avoid burnout in teaching in general, or in taking on something like classroom design, is to focus on what is necessary (the Big Idea) and to do as
Oh, one more thing. Want to keep a little clarity? Write a journal or a blog (but don't necessarily make it public), but only for 12 minutes (use a timer) at a stretch. It will help you vent and when you read back on early entries, you'll see how far you've come or remind yourself of how you tackled things in the past.