When you explore, check everything. Look for things that stand out. When you try to jump over a short wall, use running-jump or side jump roll, and when you try to jump over a tall wall, use jump and hang. Shoot early, even when you just hear the animals but haven't yet seen them, especially in later levels. You will meet the animals as soon as you start the levels. There's a pretty good amount of ammo and new weapons throughout, make sure you pick them up. Go through the training (choose Lara's home at the game's title screen to get to the training mode).
Mirror 1
Mirror 1