Equip your best Sword Barriers, then go to a dangerous area with your team, such as an area where there are snipers, like the Fourth Area dungeon. Set the difficulty level to Extreme so enemies such as the snipers can perform a one-hit kill. With your Sword Barriers, you should not die, but your teammates will constantly get hit and killed. Simply revive them to get +5% affection. Repeat this process as many times as desired with any characters.