Felix said:
So the question is: how do you introduce her to the rules and the institutions of the game without freaking her out or overwhelming her? Do you run a mock-up 1-on-1 session? Make a few characters? Take her through your own construction of a character? What've you done?
I recommend the 1-on-1 session. Or get together a couple of people you trust to run a small 2 or 3 PC session.
I say people you trust because, IME, most gamers are the worst ambassadors for the hobby imaginable. They either ridicule people as "noobs" or, quite cluelessly, overwhelm them with all types of advanced strategic advice and gameplay analysis that is utterly meaningless to the new player.
It's like trying to learn Chess from people who either (a) mock you for falling prey to the Queen's Gambit; or (b) regale you with detailed analyses of Bobby Fischer's tactics with segues comparing them to Kasparov's play.
Here's what you do:
(1) Skip character creation. For a new player it's an exercise in manipulating a bunch of numbers which mean absolutely nothing to them in utterly arbitrary ways. Instead, pregenerate 1st level characters from the four core classes: Cleric, Fighter, Rogue, and Sorcerer. For the Cleric and Sorcerer prep index cards with the descriptions of their spells. (For the Sorcerer just give her the spells she knows. For the cleric give her the spells she has prepared, but have a few other options ready so that she can select her own spells after playing for awhile.)
Encourage her to play the Fighter unless she has strong preferences otherwise.
(2) Explain the basic gameplay dynamic to her: "You (and the other guys) are all playing specific characters. You're like an actor playing that part, but you don't have a script: You decide what you want your character to do. I, on the other hand, am the DM. I create the world in which your character lives: So I'll tell you where your character is, you'll tell me what you want your character to do, and then I'll tell you what happens."
Note: When explaining things to her, use examples from the literature she likes. Talk about Aragorn doing stuff in LOTR or whatever.
(3) Explain the core mechanic: "Remember when we were kids and played Cops 'n Robbers? Remember the endless arguments about 'I shot you', 'no you didn't', 'yes I did', 'no you missed'? Well, D&D avoids that by using game mechanics to determine whether your character succeeds or fails at a given action.
"Your character's abilities are defined with numbers -- the bigger the number is, the better your character is with it. To resolve an action, we roll a twenty-sided dice (like this one), add the appropriate number to it, and then compare it to what we call a Difficulty Class. If your total from the die roll is equal to or higher than the Difficulty Class (or DC), your character suceeds. If your total is lower, though, your character fails."
(4) Explain ability score checks and skill checks. These are pretty easy: Just show her where the numbers are on the character sheet and explain that, for example, when your character is trying to jump across a chasm they'd make a Jump check by yada yada yada.
(5) Explain combat, but keep it simple. Leave out all the special maneuvers, grappling, disabling, and what-not. Focus on the core mechanic, which boils down to:
(a) Everyone makes an initiative check to determine who goes first.
(b) Everyone takes turns. On their turn they can move up to 30' and do something else (and something else can include "move another 30 feet").
(c) Make an attack roll.
(d) Compare it to AC.
(e) If it hits, roll for damage.
(f) Substract damage from HP.
(g) If HP drops below 0, you're dead.
(6) Your pre-gen characters probably have 2-3 special abilities and/or spells. Now that she has the basic mechanical understanding necessary to understand them, take a minute and explain what these options are.
(7) Start playing. The total explanation should have taken less than 10 minutes and consisted of less than a dozen or so concepts. Anything more than that and you're making it Too Damn Complicated.
I recommend starting with a relatively simple scenario with lots of opportunities for using the mechanics. In media res isn't a bad way to go, either.
For example, I would suggest starting with something like: "A goblin has stolen the purse of gold coins your father kept hidden in the barn. You've followed the goblin to the small cave you now stand in front of. What do you want to do?"
As they enter the cave, ask for a Listen check (to detect a noise coming from deeper in the cave). Past the first chamber describe a chasm in the floor that needs to be jumped or climbed across (make the appropriate checks). Put in a crude, locked door (Open Lock or Strength check). Beyond the door run a short combat sequence against the goblin. Have her make a Search check to find the purse in the goblin's warren.
The purpose of this short sequence is to help her get familiar with the mechanics: Then, after that, I'd try to hook her into a wider story that will whet her appetite. Maybe her father has been killed when she gets back to the farmhouse. Or it turns out the goblin has a magical gem that attracts the wrong sort of attention. Or whatever. You know her personal tastes in fantasy better than I do (obviously).
One more tip: Dungeon crawls are a great introduction. They constrain player choice, but they also suggest it. (When in doubt, kick down the next door.) This means that the new player is never stuck wondering what they should do next. (This is the secret of D&D's success, although a lot of more experienced players forget it.) If it seems like she isn't sure what to do next, don't be afraid to suggest a course of action to her.
Over the course of the first session you should move from simple stuff that helps her get comfortable with the basic and abridged ruleset you're working with to more interesting material that will help her to see why the game is fun to play.
Justin Alexander
http://www.thealexandrian.net
. I think that different people approach the game differently, and if you want to get someone involved you have to appeal to their player type. My wife's last character was a screaming, blood soaked, barbarian whose last concern was fashion sense. She did, however, enjoy breaking things. I'm just saying that it might be a touch insulting to a girl to be like, "Oh don't worry your head with all that stuff, just decide what you're wearing!" I know that you didn't mean it like that, but if you make the "girls play different" assumption, you might wind up in the dog house for a while 
. Hell, my wife has a degree in physics. She can do most of the mechanical parts of the game a lot better than I can!
