Picking Targets 🔪
The first thing to establish is the hierarchy of targets, from "Should Die Immediately" to "Don't Touch Them At All": Crewmates that did visual tasks, Regular old crewmates, Crewmates that the rest of the crew are already suspicious of.
Crew that have been verified must die immediately. If they make it to the end game, process of elimination means you can't throw doubt on them. Ideally, you kill them during the verification process as they are vulnerable during the animations.
That goes for crew too. Try your best to remember if someone was verified earlier in the game, as a lax impostor who tries to throw doubt on the wrong person is done for.
Meanwhile, crewmates that the crew are suspicious of should remain untouched, as the crew will likely vote them off themselves. This also means an extra person to take the heat off of the impostors. If that person ends up being your partner, don't try to aggressively defend them or you may join them soon enough.
Next to consider are witnesses. If you were hanging with the target for a while before the kill, people are going to point fingers. You can throw the heat off a tad with a separation or isolation sabotage in the middle (which you go to fix) as that casts a bit of doubt about you actually being the one to kill them. You can also close doors to block vision, but this doesn't work if people saw you go in with them, even if you vent out.
While generally you shouldn't kill in the open, there are times where you'll be forced to, or can take advantage of.
If a group of people cluster on one task, like fixing lights or one of the Common tasks, a kill in the middle will cause pandemonium as it'll be difficult to tell who actually did it if everyone was staring at the menus. Do be careful with cluster kills though, as the Imposter lunges towards the target, and you can't be 100% sure that you locked on a target that's basically in your space. This lunge will get you called out.
With a lights kill in front of the panel, vision is impaired so the crew can't see people walking at the edges of the screen like they would normally. This allows you to vent away too on Skeld and Mira HQ, leaving them with that sticky situation I mentioned in the Do's and Don'ts of Sabotage.
Additionally, the final kills of the game can be completely brazen. If you still need a double kill, you'll have to coordinate with your partner. Setting up a sabotage is a good first move, as that can both stall out a cool down, and ensures the position of the vast majority of the crew. Watch your partner carefully. If they seem to be hanging around close to a potential victim, you should signal that you can or can't kill at that exact moment. Ignoring their signs and/or leaving them should hopefully put them off a kill you can't pull off. The best time to set up a double kill is right after the round starts as each time a round starts, the kill cooldown for the impostors is reset. That way, you can ensure you are in sync.
Don't kill your victims right beside each other as a slow second kill means the living victim can still report the other body. Ideally, wait for them to do tasks nearby, especially if one of them is a long one that covers the screen, like Start Reactor.
Finally, as an Impostor, you might just put yourself in a bad situation sometimes where someone walks in on you right after a kill. Two big steps here, report fast, accuse fast! In Among Us, emotion still rules, so a confident call out supported with the microphone of reporting can muddle the waters enough to stall out the discussion timer and being quick makes the other guy look suspicious first. Of course, you can only pull this stunt once, so you'll have to use all your sabotages and stalls to prevent the crew from voting you off the next round.
As a last tidbit, in between meetings, non-verbal communication is key. A big one to mention is the "wiggle" (I don't really have a name for it beyond that), which is basically just rapidly changing direction on the spot.
(the gif is a bit fast, you don't need to be that quick or tight with it.)
This is the attention grabber. From there it's a matter of walking back and forth between the person who's attention you've picked up and the direction you want to direct them to. You can use the wiggle to lead someone into a trap, to convince them to watch you do a visual task, or to get your partner to kill the other dude already so Impostors can win.
Wiggling can also be for fun, like being happy that someone else did a visual task.
Alternatively, just standing in front of a room/section with a task in it. Eventually, a passerby will follow you inside a bit. This one only really works with the big tasks like Submit Scan in Medbay or Clear Asteroids on Skeld and Polus as they are visual, or with rooms that are dead ends and a single crewmate would be afraid of, like Electrical. You usually can't coax them in further than they need to be to see you unless you turn out to be the real deal with a visual task.