Don't worry, there is a TL;DR at the bottom lol.
Basically, spread out in duos (and stay in your assigned duo!!!!). If they kill their partner they are immediately held accountable by the rest of the crew, if the impostor does anything sus, they can always go to emergency, and if the impostor kills anyone they can report. What this does is create an "if not me then it's them" situation in the duo. This is the best-case scenario for crewmates since they can just kill off both people in the duo since it's practically confirmed that one of them is an impostor. Boom. You disarmed the impostor. The only possibility of the impostor winning is this. Red is the impostor and blue is their assigned partner. There is another pair of crewmates (Green and Yellow). Red waits for blue to do a task that takes up a long time and covers the vent on the screen (e.g. Simon Says on The Skeld) and vents out undetected. He then quickly finds Green and Yellow, in hopes that Green for example is doing a task that covers up Yellow's location or vice versa. Red kills yellow, he vents back to blue who is hopefully still doing Simon says and has no idea that red disappeared and fakes tasks like nothing happens. ONLY INFINITE IQ IMPOSTORS CAN PULL THIS OFF. You need to have a knowledge of the space EACH TASK takes on the screen, which is incredibly difficult. You also need to have a shit ton amount of luck, since you need your partner to have a long and vent-covering task (very rare) and at the same time have to find a duo which is in the same position (even more rare!!). However, if you do pull this off, you have effectively managed to dismantle the system. When they eject the partner of the person you killed (which by the logic of my system, should be the impostor) the game should end immediately. When the other crewmates see that the game has not ended immediately, they realized that the system has failed them, which will result in them splitting up, which means you get a much higher chance at winning. Actually, considering you pulled such a crazy thing off, you can probably easily win that game with your skillset.
P.S.: This can also be employed, more practically, in the middle of the game when you have kill confirmation and ejected an impostor with an even number of people left.
TL;DR: Spread out in duos when if the amount of people is even and there is one impostor. This results in a 99% crewmate win. Read the whole thing if you want to know why it works and what is the 1% situation 😉