Finishing Native quests with a positive outcome for them is the way to achieve this. The attitude towards you needs to turn "Friendly".
Most are on side quests.
The Battle of the Red Spears
• Must follow Siora's path
The Demonical Cult
• Must follow the nervous man without fighting him
Siora's Quest "Find Queen Blánid"
Attack on Caravans
• Convince them to leave without bloodshed (high charisma helps here)
• Just follow the quest through
• Another simple quest. But when it comes to the hunters. You MUST make them confess through dialogue.
The Blood Prince
• Release the Slaves. This quest is ridiculously annoying on Extreme difficulty, make sure you take a few resusitation potions and take Kurt with a weapon that does high shield damage.
Once the outlined quests are done the trophy should pop.