We’ve talked about the principles of good design, but principles only give you a way to evaluate and improve an existing design. But… how do you figure out what the dang design should be in the first place? Many people write big, functional outlines of all the features they thought up. Then they design each one, and hang it off of a menu item (or web page). When they’re done, the program (or web site) has all the functionality they wanted, but it doesn’t flow right. People sit down and they don’t know what it does, and they don’t know how to accomplish what they want.

Microsoft’s solution to this is something called Activity Based Planning. (As far as I can tell, this concept was invented by Mike Conte on the Excel team, who got bored with that and went on to a second career as a race car driver). The key insight is to figure out the activity that the user is doing, and focus on making it easy to accomplish that activity.

Read all about it in Chapter 9, the final installment of my book on UI design.

About the author.

I'm Joel Spolsky, co-founder of Trello and Fog Creek Software, and CEO of Stack Overflow. More about me.