I have some pretty clear slices in my day:

Mornings I have a clear head, and can get a ton done in a compressed timespan. Afternoons are good for a grind; I've mostly blown my clarity for deep cognition. And after about 8pm, I can start coming up with innovative ideas, most bad, some good.

I try to keep myself on track by continually asking myself, "What do you need to do? How do I get there", and sketching it out.

Often, like Rands, I just need to stare at Hacker News or some other site until my creative thoughts come together and a strategy forms. Usually I am at work, so I have to go to lunch instead when that happens, or find something else to occupy my time with instead of doing the 'creative disengage'.

Ah well.