Some consistency comes from reducing the number of times you must persuade yourself.

Every repeated decision is another opportunity to talk yourself out of something. If going for a run, sitting down to write, or calling your mother has to be argued for each time, then consistency depends on winning that argument on tired days, which is not a reliable arrangement. Making it a fixed feature of Tuesday removes the negotiation entirely.

Take the thing you want to keep doing and attach it to a fixed time or an existing routine this week. Stop treating each instance as a fresh choice. Defend the slot rather than your motivation.