The first step in becoming an S-Tier Impostor, is by faking tasks. Only Crewmates can complete tasks, so faking one when other players are near can give you an alibi. To fake a task, stand still in the task spot and wait a bit. Try to leave just after the task bar in the upper left corner fills up, to prove that you really did it. Note that many players will be doing tasks in early game, so you will have many chances to fake them perfectly.
Be careful not to "finish" your task too early though! While most tasks do not take more than a few seconds to complete, there are several long ones. An experienced Crewmate will become suspicious if you pretend to do a long task in two seconds. It is therefore useful to learn which tasks are long ones, and which ones are short. Finally, you should stay clear of the tasks that are visible, as you can't fake those.
Not being able to fake certain visual tasks means that when a Crewmate completes these visual task in front of others, they are 100% in the clear. If you're the Impostor then the choice is between you and them: if they accuse you, you will lose the game. In other words, you must kill immune players as soon as possible.
It is important to kill immune players quickly. Don't take your time and kill other Crewmates first, because that will only increase your chances of becoming the prime suspect. But don't be reckless either: if you're up against experienced Crewmates, they may be shadowing the immune player to see if the Impostor reveals himself. Use sabotage to isolate the immune player.
Talk, vote and accuse as if you were a Crewmate. Be as honest as possible about your own whereabouts, and don't be too aggressive. If you start yelling "it's blue!" without a good reason, others will look at you with suspicion. Even if your early game aggression leads to another players eviction, you will have drawn attention to yourself and likely be next to go.
Furthermore, Crewmates are less inclined to suspect you if they think you're a bit of a noob. An occasional "who should I vote for?" or "I don't know the name of the room" are subtle ways to help you achieve this. But do not exaggerate; players who continuously emphasize that this is "my first time playing, please don't kill me" are bound to get voted out.
You want to stir the conversation in the right direction, so don't wait for things to go wrong. After a murder, you might want to casually ask another player where he came from, or what tasks he did. Crewmates cast accusations all the time, so joining in is not necessarily suspicious. If you do so early on, Crewmates may pick up on your accusation and start suspecting your victim.
This rule is even more important when you encounter a witness. If another player saw you near a dead body or even kill someone, you know they are going to accuse you. A defensive position is usually not a strong one, so try to either accuse them first or explain yourself before they get the chance. For example, if Pink saw you walking close to the body before he reported, subtly mention that it was not Pink, as you both just walked into the room where the body was found. If Pink then starts questioning you, you have already explained yourself and are therefore more reliable.
Naturally, you want the crew members to eject as many of their own as possible. But in early game especially, your priority is to build up your own credibility. Covering for another player may therefore be a wise move. A phrase like "I think I saw pink complete a task, he is clear" will make you look trustworthy. With any luck, the player you covered for will remember that and be less inclined to vote you out later in the game.
Additionally, it can be wise to save an innocent player from elimination. If you create a tie between two Crewmates, the next round is still all about them. The Crewmates are wasting Meetings while you remain in the clear.
When at least four players are standing on the same spot and one of them gets stabbed to death, it is very hard to determine who the killer was. You, as an Impostor, should make use of that.
So how do you get enough players in one place? As the numbers dwindle, it will be more and more difficult to find such a crowded area. But in early game you can, for example, sabotage the reactor. With some luck, many players will gather in the same spot to fix it. Pretend to be running to fix the reactor alongside them, wait a few seconds while everyone gets started, and then strike. Don't forget to act surprised!
Much like a crowd kill, you can use your sabotaging skills to lure people away from a crime scene and keep them from reporting the body. Want to do a vent multi-kill? Start by waiting for your victim inside a vent, then kill, sabotage, and jump back in. Once Crewmates fix the sabotage and your second victim walks in, jump out and kill them before they can report the body.
Note that this will only work in early game and not for an unlimited number of times, as your absence in the emergency area may get noticed.
Impostors often overlook the presence of cameras on the Skeld and Polus maps. A Crewmate watching the cameras might see you stab someone, so beware. You can see several cameras hanging on the walls of both maps. If you see a blinking red light, you know someone is watching you. So don't stab the next Crewmate that comes along.
The cameras are not just there to hinder you though. Crewmates watching the cameras can't see other players next to them, so if you see those little red lights, it may be time to pay the security room a visit. Furthermore, you can pretend to be a Crewmate by watching the cameras yourself.
This is very important. If one more kill brings the number of Crewmates down to the same number as the Impostors, you have won the game! Just kill another Crewmate as quickly as you can.
Quite often, Crewmates are not even aware of this. However, if they are a bit more experienced, they will try to call an emergency meeting as soon as possible to prevent the Impostor from making their final kill. The best way to fix this problem is by sabotaging immediately. During a sabotage, Crewmates can't call an emergency meeting and are forced to walk over to a certain spot. All you have to do is wait for them to meet their fate.
We're not saying that this is the most honorable way to win, but it is an entertaining one. Just stand still and wait. Others will notice you're not moving, assume you're AFK, and leave you alone. When a player comes in range, walk towards them and quickly kill them. Then go back to the exact same spot you were in. You will be surprised how many players buy into this tactic.
Unfortunately, this is unlikely to work a second time in the same group of players. But if you're playing with a group of friends and want to make memories that last a lifetime… Being the ultimate Impostor-troll is the way to do it.
Unlike Crewmates, Imposters can move around the map much faster by hopping in and out of vents - the small, grey grills on the floor. You can lurk in these as you decide which room to travel to next, but your sabotage and kill cooldowns will pause while you're out of sight. Before dashing out of a vent, it's worth waiting a few seconds to see which Crewmates are nearby - you want to avoid appearing in front of them and giving yourself away.
As the Imposter, your objective is to sabotage and pick off Crewmates, but you need to have backup tasks in mind to help you blend in with the rest of the team. Pick a few tasks you can claim you've been working on between meetings so you're ready to reel them off with confidence, when questioned. This is a solid Among Us strategy, but it also helps if you're good at lying. Remember that you cannot fake visual tasks, though—that's one way to admit you're the Imposter immediately.
Heading to terminals and pausing for a few seconds to make it look as though you're getting on with your tasks also helps. Others will be watching, and good Crewmates will highlight those who aren't completing tasks in meetings. After you've played for a few hours you'll notice ways in which you can build a convincing defence, while seizing opportune moments to pin the blame on others.
Switching off the lights, breaking the Reactor, and sealing doors are just a few ways that you can slow down the Crewmates and orchestrate a kill. There's a cooldown after executing a sabotage event, so plan ahead and think about how you can target players and get away quickly afterwards. Killing close to vents provides you with an escape route, but consider locking a Crewmate in the room with you to avoid them leaving, or someone else entering and witnessing the attack.
Turning the lights off restricts Crewmates' vision to help you perform a quick kill, even while others are closeby, before you slink off to another part of the ship. You can even trigger sabotage events that require Crewmates to fix the machinery, and then fix it yourself to appear innocent.
Gaining others' trust can be challenging, but you can try to frame an innocent Crewmate by reporting the body of a player you've killed. This strategy is certainly risky and can easily backfire if other Crewmates are already dubious. However, if you've played carefully up until this point and have managed to get others to clear you in previous meetings, hiding in plain sight can work surprisingly well. Similarly, if you're aware that the crew suspect an innocent player, reporting the body while they're conveniently close by helps you to build a persuasive case against them, and removes you from the ejecting line.
This Among Us strategy is difficult to pull off, but it can end games quickly. If you're in a match where there are multiple Imposters, be sure to keep an eye on what they're up to. You may not be able to speak to them, but you can work out what their intentions may be based on the sabotages they're initiating, as well as their movements and positioning on the map.
Operating separately ensures you'll each have different Crewmate alibis, but you can vouch for each other, providing your stories are plausible. Towards the end of the match, when few Crewmates are left, or when they may be close to completing all tasks, teaming up with the other Imposter can close the game quickly. Choosing a sabotage that benefits you both, such as switching off the lights, could lead to a double kill. This ensures you're making the most of your time between cooldowns.