Seeing AW from the players' side for the first time made me appreciate (again) just how powerful and useful a (DM/MC/GM) tool questions are. I must admit I'm seriously underusing them in my games, and often forget about asking leading, provoking or just detail-fishing questions.
So a player introduces his character, and you ask him "what do you look like?" or "what are you wearing?". Old stuff, it's just about establishing your fictional persona at the table. But then you push a little further. A player describes his viking warrior. "So you're wearing a fur coat, yeah? Who made that for you?" That sort of questioning can build so much stuff about the world, the community, the character's background...Things come from somewhere. You're not a freshly-spawned avatar in a videogame. You have history with these people around you. You've been living in this world for ten, twenty, thirty years. What's it been like?
I don't want an elaborate backstory, or a fanfic about your character. We're here to play his story, the story is about to happen, you don't have to write a novel about what happened before we started, that's not the point. But we have to get a feel for him, and questions are an awesome tool to do that, if you wield them right (I rarely do).
Of course, the player you're questioning must be collaborating and pro-active. If he's cautious, shy, turtling, obstructionist or whatever, you're not going to get anything out of him. "Those boots? Oh, I dunno, I just bought them, somewhere."
But if he's not, every answer can beg a further question or two. "Bought them, cool. How did you earn the money for them?" "I'm a crafter." "Cool, what do you craft, where did you learn how to do it?"
In my initial description of Waiter, I mentioned that he's wearing hiking boots. It was just a spur of the moment thing, an offhand comment. But, you see, this is Apocalypse World. They don't make hiking shoes anymore. So obviously it's the MC's job to barf forth apocalyptica all over my shoes. He hasn't done so, yet, but he has every right.
Actually, screw that, it's not that he "has the right", it's pretty much that I want him to do. If he won't, I will. Or maybe we'll just forget and ignore the shoes, maybe they won't be relevant to the game, ever. Doesn't matter.
But if they do come up, they can be an excellent way to establish colour. So when the MC does his job [hypothetical situation] and asks me "where did you get those shoes?", I'm sure as hell going to say "Took them off a dead man.", "Did you kill him? Have you killed a man before?", "I bashed a fucker's head in once, but I haven't killed. Found him dying by a creek. Poor bastard dank our water, never knew it was bad for him.", "Do you know where he came from?", "North. Must have been. Only place a man might still find good shoes." [/hypothetical situation]
All that from a pair of fucking shoes. Asking questions, building on the answers. Saying yes, yes, and. Asking for details.
Post Scriptum: Good Answers Are Important Too
Note, I'm not planning this ahead, I don't have a backstory for my character. Maybe if the MC does ask me, I'm going to answer something completely different. Maybe he won't ask about my shoes but my shirt. Or my ham radio. Or moonshine. When answering I will consider these guidelines:
1. Say something obvious. This is a rule of impro. If you try to come up with something intricate or clever you'll just fuck up. Just say something straightforward.
2. Say something cool and interesting. Do this by leaving room for something more, don't finalize your answer, create more questions than you made answers, create a new mystery, throw other players a bone, do something provocative. Don't be bland. This might seem contradictory to "something obvious" but it's a fine balance. Don't try to be clever, do be provocative.
3. Be short. Couple of sentences. Sum it up, don't ramble.
4. Consider the setting. Stay true to the spirit of the game, if it's AW, barf forth apocalyptica (yeah, it's not just the MC's job). If it's a viking game remember the cold, the raw materials, the family bonds. If it's a horror game be gloomy, creepy, disturbing. But also build on the setting. I got these boots, yeah? Who sewed them for me? My uncle? Bam, new potential NPC. Add colour. Paint the world with your character as the brush and his life as your palette.