Day 15: Consider the time to publish your game
Most digital stores nowadays ask you for a few days to review the build of your game and approve it. In the case of Steam, you must wait at least 1 month since the purchase of your first app credit (basically the token to publish a game), along with 2 weeks of store presence and the game build review (around 1 week).
Consider these lapses so you can release your game in time! This is especially important in games related to a specific date, like a holiday, so be careful to not let the dates slip and miss your initial release date due to these processes.