Valor will prefer to mark enemies you attack. He also will mark minions to help you last hit.
Vault is powerful but must be used with caution, as enemies can attack Quinn when she strikes them. Vault can sometimes be used to cross terrain if your back is to a wall.
Use Tag Team for traveling very long distances quickly, for fleeing from enemies, or for chasing wounded targets.
After being marked, move away from Quinn so she can't take advantage of it.
Keep tabs on Quinn's position. Tag Team can enable Valor to cross the map very quickly and attack you by surprise.
Valor gains a huge amount of Movement Speed when he's out of combat. Deal damage to him to slow him down.