Day 2 of 90 · Start small
Write one if-then sentence
“"If I finish my morning coffee, then I walk round the block." One sentence, and I know exactly when.” — Kai

Today's action · 5 min
Turn your habit into one sentence: "If [a moment in my day], then I will [the habit]." Write it on a sticky note and put it where that moment happens.
Why it works
These are called implementation intentions. Across 94 tests, Gollwitzer and Sheeran found that if-then plans had a medium-to-large effect on reaching goals. Deciding the when and where in advance means you are not relying on remembering or feeling like it.
Source: Implementation Intentions and Goal Achievement: A Meta-analysis of Effects and Processes (Gollwitzer & Sheeran, 2006)
Educational content, not medical advice. If you are struggling, contact a qualified professional (Lifeline 13 11 14 in Australia, 988 in the US).