Extremely detailed microtasking. Like this: http://taskulus.com/taskulus17.png or http://taskulus.com/taskulus16.png

Each of these is a very small tasks that 1-20 minutes but it's important that I can devote my complete concentration and focus to it, without the need to load everything else in my brain.

That of course requires a lot of what SICP calls "deferred decisions" and so units of my code are forced to be much more independent.