Day 1 of 90 · Start small
Pick your Day 1 on purpose
“I used to start "someday". This time I circled a Monday, and it already feels different.” — Kai

Today's action · 5 min
Write today's date at the top of a page as Day 1, and under it one habit you want running by the end of January. Keep it to one line.
Why it works
Researchers Dai, Milkman and Riis found that searches for "diet", gym visits and goal commitments all rise after fresh-start dates like a new week, month or year. They suggest these landmarks help us file past slips under an "old me". It is a nudge, not magic, so use it to begin, then let the small daily steps do the work.
Source: The Fresh Start Effect: Temporal Landmarks Motivate Aspirational Behavior (Dai, Milkman & Riis, 2014)
Educational content, not medical advice. If you are struggling, contact a qualified professional (Lifeline 13 11 14 in Australia, 988 in the US).