To me, Scarcity is the type of conflict your players are interested in and hinting at without knowing it.
I just started a new AW campaign recently as well so I'll tell you what I did.
Character Creation offers a lot of info, especially the Hx phase. It's not enough to say "my character doesn't trust you". Demand why and/or what happened. (The Battlebabe decides the driver is a perv that wants to get in her pants). Even during chargen I'm furiously scribbling notes and filling in the 1st Session Worksheet. The Driver says he lives in a junkyard with a mechanic/tinkerer of sorts- boom, written down, npc gets a name, etc. Chargen is collaborative effort with the whole group playing pretend. So for my group, chargen is already the beginning of the "1st Session".
During the 1st session our group describes their Apocalypse World with a holding that detoxes water from a toxic lake and trades with trader caravans from all over the wasteland. I get they are probably not interested in Hunger or Thirst. But they talk about how the holding is begrudgingly governed by two brothers...Hmmm, Ambition fits the bill. They want slavers and raiders and cannibals, so I list them under Hunger. One of the player's says his character wishes he could go to this 'high-class' whorehouse at the top of a cliff where the Battlebabe used to work- Envy. The Gunlugger says he found the blasted ruins of a military base in the wastes where he gets his ap ammo (you think nobody else is going to find it!?)
That Battlebabe says she does odd, shady jobs for the Hardholders (npcs) and trading caravans (Thirsty caravaners). The Gunlugger says he used to do security jobs but is tired of it. The driver says he is like the postman and delivers packages and visitors to another hardhold.
So... after 1st Session I'm making a Front. I look at the worksheet and ask myself, "Whose Envy threatens the PCs?" For each Scarcity. I rephrase the questions to get me to think differently, "How does _______'s Hunger threaten the pcs?"..."How might the Players' Scarcities draw threats?"
I definitely see an opportunity with the dual governing of the Hardhold. And I have written the most notes under Ambition, the players must be interested in conflicts of Ambition. They even said the Hardholders are brothers that grudgingly share leadership. I decide one of them is going to make a move and write him down as a threat.
Threat: Brother Mercer Warlord/Collector (Impulse: to control)
He's got a gang and a compound
What else have I written down that could have a strong Ambition, even if I listed it under a different Scarcity? Well there's the Maelstrom, the players were really interested in that. How could I make (express) the Maelstrom's ambition? I decide, based on the players' description of the Psychic Maelstrom, that it wants to possess people...even things... The player's suggested during the 1st session that it could be the souls of all those who perished during the Apocalypse....
Threat: Outwalkers Brutes/Cult (Impulse: Victimize & Incorporate People)
Custom Move: Spectral Torment
Outwalkers manifest spectrally or physically through a claimed/possessed individual during freak lightning storms (A storm just sort of happened during our 1st Session when the Driver failed at Opening his brain. Then a passenger went nuts and ran into the darkness. These storms are dubbed "Darkstorms"). In a Darkstorm, outwalkers manifest as spectres and most moves against them will use Weird.
Now I read where the group wanted slavers/raiders but I put them under Hunger. Could they have an Ambition? Then I get a brilliant idea as I think back to the Hardholder, what if he tried to hire some raiders! But that can't happen yet, I gotta let a story unfold, so this idea goes under the "I wonder..." section. Then it comes to me! How about a whole army of new raiders just moved into the territory and they want to claim it!
Threat: Keeler's Army Brutes/Hunting Pack (Impulse: Victimize anyone)
2 or 3 harm gangs/ 1 armor Bike Gangs (the players got attacked by a bike gang in the 1st Session)
Drugged up Suicide Slaves (5-harm area loud messy) no armor
Why is Keeler so powerful? Maybe he has a fucking tank!
Well that is three threats that revolve around Ambition, I call it a Front. But it doesn't seem like enough threats since one kind of just happens infrequently (Darkstorms). I remember the group wanted mutated animals and that traveling was supposed to be dangerous so I write up the Home Front to include:
Salt Water Infection (since the setting is the Salt Lake area...the lake is toxic and disease ridden in AW)
Custom Move: Roll+Cool when you ingest the water. On a 10+ you're okay. On a 7-9 you look and feel like shit but you'll get over it (-1 Ongoing). On a miss, you're fucked and will need an Angel (1 harm and -1 Ongoing).
Water Cats (semi-amphibious mutated cats)
Group of them count as (2-harm/1-armor)
They also transmit the water infection with their claws and teeth.
Rattle Snake (Fucking Huge!)
Bite kills almost instantly (Hard Move for a complete miss. Player must take a disability to survive)
Constriction 2-harm ap/ 2 armor
I write down appropriate countdown clocks for the Threats in my Front. This is done by asking yourself, "What's the worst that can happen if this threat is allowed to totally run free?" This becomes your 12 o'clock entry on the countdown clock. For your 1-3 o'clock entry ask yourself, "How does it start?" Then go to 12 o'clock and work backwards from there, "What has to happen before that?....What has to happen before that?"
For example with the Psychic Maelstrom's Outwalkers I decide that at 12 o'clock, "Storms and Madness across the land".
How does it start? (1-3 o'clock), I fill in, "Hauntings".
6 o'clock becomes 'possessed machinery and vehicles'.
9 o'clock, 'Surge of Mutant Crazies'.
10 o'clock, 'communities incorporated'.
11, 'Becomes Entrenched'.
After I write the countdown clocks for each threat in this Ambitious Front. I tie all the 12 o'clock outcomes together for the Agenda/Dark Future of the Front, "Psychotic Cannibal Badlands".
Does all this help?