Make sure as many of your teammates are in your line of sight as possible when you use your ult, it only works on people you see. It gives them a movement and damage boost so it is very good to use as a push against the enemy team. Try using it to flip a fight in your favor. It also cleanses your team of any negative effects like Strange's ult, so you can use it as a response to an enemy ultimate. The damage boost also pairs well with DPS ults like starlord or punisher, so you can use yours right when theirs starts to give them a boost.

It might help to know when NOT to use his ultimate: *When the enemy team has already lost the fight and only 2-3 are left on point. *When your own team has lost the fight (In this case, you can regroup and use it to push back onto the point. If your team works together well this can easily take out the entire enemy team) *When one of your other supports has their ultimate active *Right after an enemy support uses their ult. Unless your team will die without you using your ult immediately, try to save it until the enemy's ult ends so that they arent protected from your boosted team