1: When you kill someone, call an emergency on the opposite side of the map. Ex: You killed someone in navigation. Call reactor/lights.
2: Try and kill in areas with a low amount of entrances, tasks, and a high amount of obscurities.
3: If there is a vent nearby when you kill, vent.
4: If the red light is blinking on the security cams, that means someone is watching. Do not kill or vent.
5: Early in the game, do not do the second part of a two part task. Some include Admin, download data, Engine, Fuel engine, and divert power to (insert room.)
6: Check your fake tasks It is advised to do these tasks, or a common enough task
7: Know your common tasks. If you have them on your fake tasks, list, do them. If not, do not. On
the skeld, the two common tasks are card swipe and fix wiring.
8: Do not do visual tasks. These include Medbay, Scan, Storage, Empty garbage/chute, Weapons, Shoot asteroids, and shields, shields.
9: In a two impostor game, try and stick with your teammate as much as possible. Attempt to preform a double kill when able to.
10: Prioritize to kill confirmed innocents.
11: Do not kill suspicious people, especially when you were the one who sussed them.
12: Prioritize to kill people who a crewmate sussed on, and no one listened. This will prove them wrong and throw sus on them.
13: Lights are the best sabotage.
14: The cameras can still see just as well even when the lights are off.
15: Do not kill someone you have spent a lot of time with.
16: After you perform a kill, go into a group of people. (safely.)
17: When you are at 5 with 1 impostor, or 7 with two impostors, you can try a fifty fifty. This is when you kill someone and blame it on them. You should only do this when you are much less suspicious then the other person.
18: If you are at 3 with 1 impostor, or 6 with two impostors, wait until the emergency button cooldown is almost gone, and then call reactor or o2. Then camp reactor or o2 and kill the first/first two that come.
19: One of my favorite kills is what I call the third party kill. You find a party of 3, Sabotage lights, kill 1, and then you leave the two crewmates blaming each other.
20: Wait until the taskbar goes up before you leave a task if someone is watching. Avoid doing short tasks because of this. If you are caught waiting at a task for too long, say that you were looking at your phone, your mother called you, you had to go to the restroom, etc.
I might add some tips in the comments.
Source: https://www.reddit.com/r/AmongUs/comments/je91gh/the_ultimate_guide_for_among_us_impostor_part_1/