Shadow of the Colossus was one of those games that I played obsessively until I fully experienced every square inch of the map.
In regard to the bow and arrow, keep an eye out for fruit and lizards. You can eat both, and both provide you with advantages.
If you're inspired to play the game a second time, make sure to wait through the credits and save your game after they're through. You'll be able to play Time Attack mode on the second play-through by challenging Colossi statues that are in the main temple, and completing Time Attack boss fights in a short amount of time will earn you special items.