I hope that all my advice made it into the book! But mostly I think it comes down to to usual sorts of things:
- Make sure everyone is on board with playing JRPG-style good guys. It's fine if some folks want to be outwardly prickly, but a heart of gold is pretty essential.
- Make sure everyone knows about and understands Share a Moment -- it's really the key to making a lot of things work.
- On a related note, use the "Ask them how they feel" GM move a lot. It can spark a lot of good roleplaying.
- When possible, try to tie things back to the backgrounds of the PCs -- this is a little tricky if you're running a pre-written scenario without pregens, but anytime you can find somewhere to re-use something someone created during their character creation instead of introducing a "new" element, it's usually a good idea.
Are you planning to use one of the Assignments I've provided as a start, or are you making your own?
Oh, and also, if you are playing online, I created a Google Sheets character keeper here: https://docs.google.com/spreadsheets/d/1O4F7S531piD-gboNIqFZIyKID0iT7psFVyLWgZnt...
You'll want to make a copy for your own use.