A lot of what @darren is saying.
Here is what prep looks like for me.
Session 0 / Everyone write the CATS together. The whole crew creation aspect is the start to identify what we as a group want the game to be about. That is our base that we continually touch back on.
Stars & Wishes at the end of every session. This rolls perfectly into the end of session xp rewards. After looking over the session we just played, what do we all want to see next? “We really want to get involved with the war in Crow’s Foot” / “Have a social score with a lot of veiled threats at a ball” / “Get more involved with supernatural elements”, etc.
It’s also not an either-or, it’s cool to have a score in mind and at the beginning of a session do the “hey, do we have a an idea of how/what your crew is going to be up to for today’s session? let’s talk about what that might look like and figure out a score together” and, at the same time, have a score in mind that you are interested in having “I got something, if you are interested, you know your contact Moriya, the spirit trafficker? yeah, she is approaching you with an offer of…”
Ideally, all your players have some ambition what kind of stories they want to see with their character and ideally, you also have things you are interested in. You can use Devil’s Bargains and consequences to set up the kinds of scores and stories you want to tell but outside of that be hands-off and let the players’ ambitions drive where things go… this creates a back and forth between everyone at the table and you get a dynamic where no one single person is steering the arc of your overall story.
It’s a fascinating and invigorating way to play!