Similar to
Cosy Creator , however I always begin a project with a start and an end. Having a start and an end means you have an actual goal to reach, and then it's all about what's inbetween it.
It highly depends on the genre, and template you are following (if any), but you can break out the writing further by putting more goals.
For example, if on day 1 the goal is meeting character A, then analyze the character and see what they enjoy... If they love coffee, maybe you'll meet them in a coffee shop... Then you'd need to find a reason for the MC to head there, maybe he works there? Maybe he's meeting somebody else there?
Answer those questions with character sheets/notes you should have beforehand, and then you'll have a rough outline of a scene with the goal you want to reach, then it's all about writing the actual scene following their personalities.