Get all the tags in a level, then play that area again in Quick Hunt mode. Press X while using the scope to see through the animals.
Complete an area in career mode, save the game and exit. Load the game and start a new career to access a new hunter. A new hunter is unlocked with each area completed.
In quick hunt mode, once you shoot the animal you are hunting, do not claim it. You should do this if you want to hunt shorter than in complete hunt mode, yet longer than the normal quick hunt.
When you get a violation for hunting a non-game animal, just go to your trophy room. When you return, you can shoot anything you want. However, this must be done after every violation.
Enter a level, then hop on your vehicle and go to the red dot that indicates an animal. When you are close to the animal, hop off and press R3 to equip your weapon and shoot the animal. If you miss, keep tracking it until you kill it.