As the crew mate you want to catch the imposter as fast as possible or finish your tasks as fast as possible so I prefer to speedrun my tasks or stick with a group of people so if the imposter kills a player then we know who it is. If you decide to stick with a group watch each player with you for suspicous acts/movements. This could mean you go around the entire map and there's one player that was with your group who didn't do any tasks, this leads to an instant red flag and you can either take action and call a meeting to vote them out or you can just keep and eye on them for anymore suspicious activity.