What I sometimes do when I need a hook for the characters is letting them describe it and go from there.
- "Ah, you guys remember your old friend, the card-shark, wasn't he a green dude or blue or something bright?...
- What was his name again?...
- Aah, of course, good old [ blank ] What did he look like?...
- How did each of you meet him?...
- You remember that story he never got tired of telling everyone about that mining outpost in the outer rim he swindled from that one sullustan governor, where was that?...
- Ah, exactly. Well, sadly he has gotten pretty ill in last year and he needs urgent help with maintaining order on the outpost since a rival mining syndicate has taken interest in the planet..."
et voilá.
You can do the same thing in the prep session or at the beginning of the first session, who was that guy that brought them to the rebellion?
PS: One day I will start a gaming group with the hangover scenario. Complete with small sullustan in the trunk, Hutt baby and Rancor in the bathroom
I think I'm actually going to start doing this on a slightly different scale, whenever NPCs show up that one of them knows from their past or saw on the Holonet or something. Any other great ideas on how to get the party more actively involved in creating the story with you?