1. Be Heroic. If you've played through Halo 1 and 2 (even if only on normal) then you should begin this adventure on Heroic. Normal difficulty is now actually easier as to cater to those who may only play one game a year. The difficulty affects enemy AI, but also will add more enemies to different areas and even allow for enemy reinforcements. While Heroic is slightly tougher than it was in Halo 2, it's also likely that you've grown your skills over time. It won't be easy, but that's the point. Don't short change yourself on experiencing everything the Brutes have to offer.