Who ever said active both passive, the opener of the thread already mentioned he has a rune page dedicated to it.
Generally your job in a team fight is to kill their carry or highest damage dealer in the team fight. You go in, mark them and proc as many times as possible avoiding the use of your crescent slash. You may use your shadow dash to help you kill that damage dealer as soon as possible if the fight turns nasty. If you run low on energy after the initial burst and completed your task. Then you have done your job. The rest it up to you to think it out and learn from experience as well. It all falls down to how the team turned out after you completed your task.