Complete every activity in a single location.
Completing most locations is not that difficult, you just need to collect all chests, song sheets, animus fragments, secrets and Mayan Artifacts in an area.
If you don't want to waste time completing a big location, the easiest would be an island called "Florida" at coordinates 409,815. Florida has very few of them. Synchronize the viewpoint, collect the two animus fragments, open the treasure chest, and pick up the bottle message to unlock this trophy.
Here is a video of this trophy from PowerPyx: