Today's WoW Rookie will not help you improve your game or your character's performance. The advice here won't help you become a "better" player; in fact, we'd encourage you to guard against the urge. As a new player in an older game (and make no mistake, with an established game world that's turned away from leveling and original content, the World of Warcraft definitely qualifies), you are quite assuredly behind the curve. You're a noob -- and that's ok. Don't let anyone try to convince you otherwise.
As a new player in the World of Warcraft, you deserve your time in the sun. It's called WORLD of Warcraft for a reason. A massive game world awaits, ripe for exploration, screenshots, wonder. Slowly peeling back the layers of lore and story reveals tales of glory, honor, humor and tragedy. This is your chance to soak it in, to bask and stretch and revel in the delightfully silly little surprises that Blizzard has scattered throughout the game.
And you'll miss all of that if your game is a tunnel-vision race to max level, purple armor and a belt notched with raiding achievements.