Brutes
The easiest weapon combo for taking down a Brute is a Plasma Pistol and Needler Rifle. If it's just a regular shieldless Brute, then unload three shots from the Needler Rufle into his body to make him explode and die. That, or use one shot to take off the helmet, then another to give a headshot. If it's an shielded Brute, then overcharge your Plasma Pistol first to take down the shield, then put three Needler Rifle rounds into the body to make it explode and kill the enemy.
We have more cheats and tips for this game here, Halo: Reach cheats
Comments for this hint