Rule #3 Focus

It can be hard to stay focused on a game when you have everyday life distractions or even just chat dialogue derailing your attention.  But always try to push yourself back in to a focused mindset so you can keep your kills/dps/micro/macro at the top lvl that you can achieve.  By doing this you will be able to get to higher ranking/better loot and this will only snowball into allowing you to easily get into the focused mindset again.