Sneak attack settlers
Strong likes things a normal Super Mutant likes. This includes murder. Sneak attacking your settlers will get you a lot of respect from it and earn you affinity. The best part is that you always have a supply of settlers. Kill several settlers (don’t be detected doing so) then go to another community and repeat.
Strong enjoys watching you kill non-hostiles. Killing hostiles such as raiders gets you a little affinity but killing peaceful civilians and traders gets you a lot. As mentioned before, settlers are perfect for this.
The Cannibal perk (Endurance 8) allows you to eat people (and ghouls/mutants on rank 2/3) to gain health. Doing this in Strong’s presence will earn you affinity with him.
Be aggressive when speaking
Choosing aggressive/cruel options will cause Strong to gain affinity. He likes strong characters, not diplomatic ones!
Strong doesn’t like…
- Power Armor
- Being nice
Avoid doing the above while maxing out his affinity.