This Trophy is for beating Olga during the first boss fight of the Tanker portion of the game. She's easy enough, just stay behind cover and wait for her to expose herself while taking a shot at you. When she goes back into cover, dash over to the other side of the screen to get on her blind side. Take a shot at her, rinse, and repeat.
There are a few things you can do to help make this fight a little easier, though. First, shoot the cables holding the tarp down, one on its bottom left and one on its bottom right. Next, take a shot at the floodlight so Olga can't use it against you.
All things considered, this is one of the easier fights in the game.