Ships in Among Us have various tasks. These tasks may be long, short, or even visual. In order to not die while doing a task, I like to "divide" tasks up. I like to do the longer tasks when I can clearly see that no one is around me. You can check this in Admin in every map. The shorter tasks are okay to do without checking for people. I like to save visual tasks for later when people begin to suspect me. I can show them me doing medbay scan so they will know I'm a friend, unless no one suspects you.
As a crewmate, finding the impostor(s) is the faster way to win than doing tasks. In order to find them, pay careful attention to where everyone is before the next emergency meeting/body report. You may notice Yellow at Electrical, for example, but they say they were at Admin, they are most likely the impostor. When someone blames a random person out of nowhere for completely no reason and evidence, they are most likely the impostor. When you see someone vent or kill, they are the impostor. Make sure to call an emergency meeting.
If the impostor notices you catch them vent/kill, chances are they will accuse you of venting/killing the person they killed. When they do, ask them for evidence. The impostor might have zero evidence to back things up, while you do. Even if they do have "evidence", it won't be as good as the evidence you have. Things still don't work? Use the phrase: "If it's not them vote me out," Then you can see the impostor fall out the ship while you wave good-bye to them, and possibly win the game.
Now we're talking about being a good impostor. The number of impostors may be 3 or fewer, but impostors have benefits: Vents and Sabotage. In the maps Skeld and Polus, the vents may lead to a few places, and to go further you will have to use a different vent. But in Mira, you can vent anywhere and everywhere. During venting, always watch out for other people and the places with cameras; no one knows who might be watching at this time. Sabotaging can be a huge benefit; get everyone distracted and crowd-kill someone. When a sabotage is not fixed in time, the impostors win right away. In Skeld and Polus, you are able to sabotage doors as well. In Mira, however, that's not an option. Usnig the doors, you can close one, kill someone, then vent away so by the time the door is opened again, all there is is a dead body.
As an impostor, you have the power to kill people. When the number of crewmates and impostors are the same, the impostors win. Killing has to be done carefully. There is a time limit until you can kill someone else, which will differ depending on which game you're playing. In some games, it may just be 10s. In others, you may even have to wait a whole minute. Killinig is done the best when you and one other crewmate are in a room, everyone else focusing on different things. Killing is best when that one person is doing a task, if they are standing there. When you kill them, make sure to vent away asap. If there is no vent, run away real fast to a random hall, or outside when on Polus. Self-reporting is a strategy too. You can tell people where you found the body and who you think might be sus.
As an impostor, you need to lie well. Not just about your location, but you might have to point out other crewmates near a body, or even another impostor if you want to gain trust among crewmates, and if you are willing to have to kill more people. You also need to fake tasks. Not visual tasks, though, because those are tasks that are visible and cannot be faked. I like to fake long tasks, because no one will suspect you when you take a minute when starting the reactor, for example, because sometimes you mess up. To successfully fake a task, stand in front of a task area(preferably long), and wait until the Total Tasks completed bar on the top left of the screen gets filled in a little. Then you can run off faking another task or killing somebody.