Relationship maps and the pitch session
This is a follow-up to my previous post about creating your characters as a group activity and the conversation you should be having about how all your characters relate to each other.
Primetime Adventures calls this conversation the "pitch session", like you are pitching an idea for a new TV show to the TV execs (and by "to the execs" I mean "to each other"). So you're trying to pin down the tone, figure out who the major characters are and how they relate to each other, what the main plotlines will be about, etc.
A relationship map can be your number one tool. Think of any show you like; you could probably draw a diagram from memory with a circle for each character and arrows indicating who's friends, who's enemies, who's sleeping together, the grudges, the unrequited loves, etc. etc. (Old-school anime fandom alert: I think Ranma 1/2 was the show that taught me this concept, or at least the first time I saw an actual relationship map on paper.)
Here's a relationship map, from a one-shot game of Primetime Adventures I played back in December. It was a near-future sci-fi sitcom set aboard a run-down space refueling station at one of the Earth-Moon Lagrange points. (Picture the outer-space equivalents of the losers who end up working at a gas station their whole lives; that was our characters.) This piece of paper shows the output of our collective brainstorming process:
(Notice we have "the station" itself as a character.) I can glance at this and remember that my guy (Biff, the surly short-order cook), is smoking buddies with Bev, works for Lydia (that arrow totally goes the wrong way), is some kind of friends with Ewan (who is an anarchist and the station's resident scam artist), and I don't yet know how he relates to Charles Smythewhiteford or Christian Turner.
Drawing a map like this helps you figure out whether the main characters are connected enough to each other -- Do they need more things in common (or more points of potential conflict)? It also helps you figure out what secondary characters (important recurring NPCs) you're going to need. And, when you think of another character to add, using the relationship map helps you figure out where to connect them.
The relationship map helps you make characters who are not just "a motley crew of strangers thrown together by fate" but rather a set of people with lives who are connected to each otehr in believable ways. Make the characters mean something to each other! You can set up love triangles, family relations, rivalries, political intrigue; the sky's the limit.
Finally, relationship maps are great for running improv games, because whenever you're stuck for what should happen next, you can just take a look at the chart to see who's been affected by recent developments and figure out what they would be most likely to want to do next.