How do I practice decision journal?

The most direct way to practice decision journal is through a focused exercise: Pick one decision you made in the past week — it doesn't have to be big. Write down: (1) what you decided, (2) the 2-3 reasons that drove the decision, (3) what you expected to happen, and (4) what alternatives you rejected and why. Time yourself. This should take under 5 minutes. If it takes longer, you're over-thinking the format and under-practicing the habit.

Common pitfall: Recording only the decision without the reasoning. A list of 'what I decided' is a changelog, not a decision journal. The value lives entirely in the 'why' — the assumptions, the constraints, the alternatives considered. Without that context, your future self has nothing to evaluate and nothing to learn from.

This practice connects to Phase 3 (Capture Systems) — building it as a repeatable habit compounds over time.