The Last Guardian is not an easy game to play. You have to be kind of smart and make use of the abilities of both the boy and the beast in order to be successful. Here are some useful tips so you can be successful in your journey.
One of the first things you have to realize in The Last Guardian is that Trico loves eating the barrels. Whatever is in the barrels, it gives him energy and motivation in order to continue.
If there are moments you notice Trico is lying down or doing nothing, this usually means you need to find a barrel or two to make him start moving again. Look high and low for any barrels you can find. In order to feed him, just chuck the barrel near his mouth.
Another thing about Trico is that he is scared of those colorful eye mirrors. If you see those mirrors nearby, you can either grab some of them and chuck them off a ledge or cliff. Other times you may need to illuminate the light mirror you got at the beginning of the game and Trico’s tail will destroy the evil mirrors.
If there are Knights holding onto the evil eye mirrors, run up to them and press Square. The boy will do a diving type move and the Knight will drop down the mirror. When the mirror is down, Trico will have the courage to destroy the Knight.
When you die, you need to button mash the face buttons and shoulder buttons frantically to continue. For some reason, the game doesn’t let you continue if you don’t do this. It’s a weird gimmick, but it’s required in this game. Speaking of button mashing, there are many Knights that try and kidnap the boy. If they grab him, button mash like crazy to escape their grasp!
The last piece of advice that I can give to you is that you need to be patient sometimes. There are times that Trico needs to transport you onto a high window, or even jump to a new area. Sometimes he is stubborn and fails to do anything. I sometimes restarted the checkpoint or simply controlled the camera to guide Trico where to go to next.