Plains of Goliath Clean Sweep Trophy in James Cameron's Avatar: The Game

Plains of Goliath is the last area you will visit in Pandora on the RDA path. There are 6 challenges in this area which need to be completed, in order to unlock the trophy.

The Sector Challenges in the Plains of Goliath are as follows:

Lift the Fog (100%)
Activating GMIs (5/5)
Installing A-PODs (30/30)
Sturmbeest Culling (40/40)
Cell Samples Collection (15/15)
Experience Points Earning (72,000/72,000)

All of these challenges and the methods to obtain the requisite criteria are covered in full detail in the Clean Sweep of Pandora - Complete Sector Challenge Walkthrough

You will notice that this trophy states to have a clean sweep for both RDA and Na'vi paths, yet it will unlock the first time you complete it with whichever side you are on so it's not the most accurate of descriptions.