Sometimes when you encounter suits of armor, there are pots or food barrels on the floor. Throw them items at the enemies. You do not have to kill them with it, just hit them. A great farming spot to do this is shortly after the first antenna room. You will reach an area with four suits of armor and a barrel. Grab the barrel, throw it at one of the enemies, and immediately restart the checkpoint. Keeping repeating until you get the "That Hits The Spot" trophy. If Trico kills the enemies, it will create a checkpoint and you will have to start a new playthrough to reach this area again. Thus, make sure you restart the checkpoint as quickly as possible. This can also be done over multiple playthroughs, as your progress carries over into New Game+.