Frames 1–2 (the obvious ideas)
The first two sketches are almost always the obvious ideas — the ones everyone in the room would draw if they had unlimited time. That's fine. Get the obvious ideas out in the first two minutes so you can move past them. Think of frames 1–2 as clearing the mental cache.
Frames 3–4 (the variations)
By frame three, the obvious ideas are exhausted and the sketches start to vary. This is where alternative approaches to the same problem emerge. The constraint forces exploration — you don't have time to go back to the obvious ideas, so you have to try something different.
Frames 5–6 (the unexpected ideas)
The most valuable frames. At this point, the obvious approaches are spent and the mind starts combining elements from different frames, borrowing from analogous domains, or simplifying radically. The unexpected ideas that appear in frames 5–7 are what crazy eights is designed to produce.
Frames 7–8 (the push)
The hardest frames. You've run out of easy ideas and you still have two minutes left. Push for something genuinely different — a completely different interaction model, a different user entry point, a solution that removes the problem rather than solving it. The push frames often produce the most creative output.