Image: Naughty Dog / PlayStationOfficial screenshot from Naughty Dog / PlayStation.
Something to Fight For is the silver trophy for finding all 12 training manuals. Each manual permanently improves a crafted item, such as shiv durability, health kit strength or bomb radius, so collecting them helps your run as well as the trophy.
Shiv: Reinforcement is locked in the Pittsburgh hotel safe, so you need the Note to staff for the code. Molotov: Deployment in The University and Smoke: Shaping in Lakeside Resort both sit behind shiv doors, so bring a spare shiv. Melee: Techniques in The Suburbs is in an attic you reach by boosting Ellie.