In that case I can probably expand a bit more.
My overall advice to anyone struggling with
flow is to restate that AW is a
Movie. Not the kind of movie where everyone is on the director/staff/actors, but the kind you all go and sit down to watch together. Cinematic flow is a narrative style, the escalation, the tension, the drama. I suppose it might be hard to picture the game around a table on the big screen, but if you manage it--maybe it'll provide a great deal of inspiration, description, and in some cases it can add in an addictive enthusiasm to the group.
This has a number of truths, first is that the movie doesn't last months. AW isn't 1 movie, it is a series. Rather then thinking in episodes however, you think in scenes. This brings me to my next point.
I've now gathered that 3 o'clock should be something serious
If we've talking threat clocks, yeah. I don't use them, or rather, I use them when things start to get out of hand or pats of the fiction seem to be getting left behind. They're more of a mental exercises and not something I'd actually use. Just writing them out correctly is often enough to tell you what it is, and you can push that when the tempo calls for it, and manipulate it on the fly to fit cohesively. This is why I brought up scenes.
The threat clock for me is the fundamental of the scene. The next conflict. The seed starter, or a bit of emotive description to prompt my barfing forth more apocalypse. The reason I don't really do this in live time, is often just the process of writing it down can lock it into what maybe it isn't. You've got to have watch a movie that surprised you when it veered off from what you were expecting right? Same deal. I do flesh out the NPCs though, ask myself who are they and what do they want, if only to inject some smaller details to make them seem more real.
Basically, to sum up. Dont use any prep that gets in your way. You should know what gets in your way better then anyone else. I think the threat clocks exist to do two things. 1) To keep reminding ourselves what the threats are/ prevent tangental things from losing focus, 2) Make sure something is always happening.