It you're really trying to get good at the game, you'd film your matches and review them after a couple hours of gameplay. Grinding games forever, doing the same wrong things over and over again, only creates bad habits. Game play logged still bring gun skill, but what's more significant to bring good at Halo, or any FPS rather is making the correct plays in certain situations.
Map awareness, spawn awareness, positioning, knowing when to run from a challenge are all things you can pick up from reviewing your games.