01 · Document the hypothesis
Before testing, write the hypothesis: 'Hook X with format Y will lift CTR for audience Z because…' Without a hypothesis, you're shotgunning, not testing.
- What ships at the end of this step — a tangible artefact / change you can point at.
- Common pitfall here: rushing past validation before moving to the next step.
- Time estimate: 1-2 weeks for foundation work.