Do Pay Attention to Audio cues
Many of the ultimates and abilities in Overwatch have audio cues to signal their use. These cues will be significantly louder coming from your enemies than it will be coming from your team. If you hear “It’s high noon” you need to hide from McCree, if you hear “heroes never die” that means Mercy is about to revive heroes so abandon the fight and regroup. Overwatch contains a whole lot of opportunities to counter enemy champions and recognizing what an enemy champion is going to do will give you an advantage over the other team. So listen and react.