A strategy method for incomplete information
Facts and hypotheses
The host knows the true roles. A civilian knows their own role; the members of a gang know only each other; the Sheriff gets personal checks. Public speeches, nominations and votes are observations, not proof. For every suspicion, write down at least two alternative reasons for the behaviour.
Three versions instead of two
For every unknown player, consider the city version, the Irish version and the Italian version. Do not call a participant a member of the city just because they convincingly exposed a mafioso: they may be from the rival gang.
The decision algorithm
Before voting, ask: what is known for certain, what is the team's aim, who else gains from the removal, what happens if we are wrong, what data will the result give.
Tools of analysis
The map of the table
For every number record the suspect, the player defended, the argument, the vote and any change of position.
Alternatives
For every signal build at least two explanations, including an innocent one.
Review after the game
After the roles are revealed, compare the original hypotheses with reality; do not judge quality by the win alone.