Part II: Foundations
Foreword
Mafia is a game of persuasion characterized by competing factions with different information and numbers. These create different incentives for town and mafia behavior which form the fundamental dynamic of the game: a hunt in which the town are attempting to find the mafia before time runs out and the mafia win. By analyzing the differences in each faction's information and numbers, we can construct a sound profile of town and mafia behavior to develop in subsequent sections on the town and mafia game.
Subset I: Information
The amount of information that individual players have regarding the state of a given game is typically different, depending on how the roles are designed and the conditions of the format. However, it is always the case that the mafia have more information about the game state than the town. They already know the answers to the town's puzzle. The town, obviously, do not know the identity of anyone that isn't themselves (again barring specific role-related circumstances). The town players start in a state of ignorance and seek to solve the puzzle, while the mafia start in a state of knowledge and seek to prevent the town from solving the puzzle.
This creates the following differences in incentives:
1. Town players have to ask questions to learn other players' alignments. Town have to solve the puzzle in a limited amount of time before the mafia win. Thus the impetus on town is to be proactive, asking other players questions that lead in a particular direction in order to determine whether or not a player is a specific alignment. Mafia players don't have to ask questions to learn other players' alignments, so their attempts to emulate town in doing so will look comparatively forced and have less direction than those of town players.
2. Town players will have a naturally evolving picture of the game state as time goes on. As town players continue to get more information and talk to more people, their understanding of the players' alignment changes. Consequently, towns favor a dynamic game where changes in reads are logical, but frequent; they're naturally capable of talking about why their reads change. Mafia players cannot have an evolving understanding of the game state because they start with complete information about the game state, and consequently they favor a static game where changes in reads are infrequent. Any attempt to discuss changes in reads is necessarily artificial and again, comparatively forced compared to the town players.
Subset II: Numbers
The two factions in mafia are defined by their numbers and their different objectives. Town players have superior numbers and need only catch the mafia before their time runs out; mafia players have inferior numbers and need to survive.
This creates the following difference in incentives, with two key exceptions discussed afterward: Town players have nothing to hide and aren't afraid of dying. This doesn't mean that they won't fight to stay alive, but all else being the same town players have nothing to hide, while the mafia do. This stems in part from their information asymmetry discussed in Subset I, but it also has to do with numbers: townies ultimately know that their death, whether through nightkill or lynch, isn't a significant impediment to their faction's victory, and they play like it.
This manifests in a number of ways: townies aren't afraid to confront people, ask questions and get into arguments, because they have no special knowledge to be exposed and they naturally discuss their suspicions; townies tend to give more definite reads and commit to particular positions, because for them deriving information from those positions, and making other players commit to similar positions, is more valuable than appearance; even more subtle things like language choice, post flow and frequency change when you don't have anything to hide.
Of course, the mafia play the opposite way; they tend to avoid confrontation and arguments because they don't gain information from them and they stand to lose a lot if they come out of the argument poorly; they tend to be more equivocal in their reads and more reticent in committing to particular positions, because it gives the town information and reduces their ability to be flexible in seeking mislynches; their language choice, posting frequency and decisions on when to engage and when to disengage are more controlled and reserved.
The two key exceptions to the above:
1. LYLO. Short for "Lynch or Lose," this is the situation where the town only outnumber the mafia by one player. At this point, essentially all bets are off; town has a significant degree of information by now, and every player, town or mafia, has an overriding survival instinct, because the town lose if they misfire. Typically you can't derive anything about a player's behavior at LYLO because the town and mafia's incentives are too closely aligned.
2. Power roles. Although town players SHOULDN'T play like they have something to hide when they draw power roles, they often DO anyway. It's a natural impulse: you have a unique ability that threatens the mafia, so of course you don't want to advertise it so you don't get killed immediately and let your team down. This is counterproductive, for reasons I'll discuss later, but suffice to say that town PRs may throw a wrench in this.
Subset III: Profiles
To recap the preceding subsets...
TOWN
* Town players are relatively more proactive, and there's a relatively clearer direction to their questions and logic, than their scum counterparts.
* Town players make reasonable but frequent changes to their reads as a result of gaining information about the game state and the subsequent evolution of their understanding of the game state.
* Town players aren't afraid of dying and have nothing to hide, which manifests in town players being very willing to argue their points, confront people with whom they disagree, and take definite positions on the guilt or innocence of certain players.
MAFIA
* Mafia players are relatively more reactive, don't naturally ask questions about the game state, and when they do ask questions the direction of those questions is relatively less clear than their town counterparts.
* Mafia players make infrequent changes to their reads as the situation necessitates; their understanding of the game state doesn't evolve as the game progresses, and so they both naturally tend towards, and prefer to establish, a more static game dynamic, compared to their opponents.
* Mafia players are naturally more defensive and secretive than town as a result of their different win condition, which manifests in mafia players being relatively unwilling to get in protracted arguments with town players, relatively nonconfrontational in general and relatively less likely to take definitive stances on someone's guilt or innocence, compared to town.
Subset IV: Basic Principles
Here are some concrete pointers to improve your game regardless of alignment.
1. You don't have to claim, or fakeclaim, or tell anyone your role at all. There are a few circumstances involving power roles where you should more or less always claim, but mostly role claims are doomed to be unhelpful in the first place; either you're vanilla town in which case you truthfully roleclaim vanilla town or you're not vanilla town and you're probably incentivized to claim vanilla town anyway to avoid standing out. As a corollary, outside of aforementioned policy situations where you always claim, rolefishing should be avoided because the results of your search can only help the mafia by giving them greater control over the night actions.
2. Make sure everyone talks. Contrary to popular belief, while quiet players are anti-town in the sense that their silence doesn't leave other players anything to use to build on, frequency of posting and alignment do not have a significant correlation. As town and as mafia it's important to get quiet posters talking; town players need to hear from them so they can clear them, and mafia posters want them talking because quiet players who aren't proactive tend to be less attentive and therefore more prone to making an exploitable mistake in their comments.
3. Read objectively. Mafia being a behavioral analysis game, you can bet that the vast majority of arguments brought forth in the game are not ironclad. Even the best of cases have some holes in them that are covered with intuitive reads or other nonlogical sources of information. Be sure to read through every post to pick out the key highlights of a case or argument against someone. This is the key to making sure your lynches go through and stopping lynches you don't like.
4. Reread old posts. That's where all your data is. Present developments are important, but it's also critical to look at what dead players said, who the major players in a given day were, what the major events were, etc. Once you can construct a mental timeline of the major events and players in a given day, you can start doing serious analysis of other players by looking at their ties to those events.
5. Everything is need-to-know. It's important to make sure that you communicate clearly your reasoning for stating a given read and for changing that read, but it's also important to make sure that you're efficient with the analysis you try to present. If you don't think a particular event is important to your read on a player, don't try to incorporate it into your analysis. Give only what your audience needs to know. This trait will tend to help mafia more than town, because it gives mafia room to present a case that deliberately excludes key details; but if you're open and forthright when other people question you about excluding a detail they think is key, then you should be able to avoid suspicion as town.
6. Play to win regardless of your alignment and don't worry about your meta. As this group continues to play games together, certain meta trends will arise. It will be tempting to make purposeful alterations to your game in order to succeed; some players will intentionally talk less and choose to be unproductive as town to provide cover for their scum game, some players will choose not to put in the work to emulate their town game as scum in order to make themselves more obviously town when they draw town. Avoid this temptation. In the long run, there is no negative impact to one side of your mafia game by improving the other.
7. Don't play scared. This should come naturally as town, but some players, particularly town power roles, will be unwilling to play as fearlessly as a town player would be expected to play, because they feel that their special powers either entitle them or obligate them to prioritize survival over scumhunting. Do not do this. Huge props go out to all three of the town power roles in M1 here: krellin, Fasces349 and Thucydides all did a superb job of playing confidently and assertively and in my mind did a good job on the behavioral front of masking their identities as power roles by refusing to allow their special abilities to compromise their fearlessness. And on the mafia side, you can't play scared either, or else you'll be caught in a town full of fearless players. I don't think the M1 mafia had a problem with playing fearlessly, so props to them too. Remember, you either have nothing to hide, or you're trying to emulate someone who doesn't.
8. Occam's Razor. Default to the explanation with the fewest moving parts, and depending on alignment, suspect or cast doubt on people who don't. The simplest explanation isn't always correct, but it's often enough correct as a starting point. Determining what constitutes the "simplest explanation" varies from game to game, but in general you want to minimize the use of recursive logic explanations (known as WIFOM, or "Wine In Front Of Me"; c.f. Princess Bride) and explanations that involve players deliberately acting in opposition to their win conditions or incentives.
9. Appearances are more important than fact. This one is CRUCIAL. Mafia is a game of discovering the truth *and* convincing people that your narrative is the truth. In mafia it often boils down not to whose answer is RIGHT but whose answer others BELIEVE is right. You might have picked out the entire scumteam by Day 2, but if your posting is erratic and you don't explain yourself, no one's going to believe you and frankly, it doesn't matter if you "caught" them at all. The reason appearances matter here is because mafia are fully capable of telling the truth as well as town. More important than WHAT is said is HOW something is being said. Mafia will tell the truth and provide objectively correct analysis; they're reading this guide too, after all. What has to be considered is whether or not that analysis is driving toward a coherent, pro-town direction.