As impostor, hitting lights is your best tool. With lights off, you can kill people VERY close to other players and they may not even realize it. A good opening move is when the game starts, wait a few seconds until your kill cool down is about ready, call lights, and just kill someone in the confusion and either make it to lights or join another group running. You often end up on a list of 3-5 people who could have done it, which is good value, and sometimes you make yourself look cleared by showing up quickly enough.
Here is one of the best kills I’ve gotten away with. I not only managed to bisect Wrapter, but I got so far away that I made multiple other people look suspicious as *I* safely got aggressive.