Editor's Note: This walk-through was performed on a druid. There will be small differences if you play a different class. Additionally, there are spoilers contained herein.
When you begin the new troll starting zones, the narrator warns you that Vol'jin knows that Garrosh could tear the Horde apart. It will come down to cunning trolls like you to keep things on the straight and narrow. As you begin the game, Jin'thala tells you that the Darkspear have always been outcasts. But this time, you're being led by the wisdom of Vol'jin, and it's time for the Rise of the Darkspear. Vol'kin sends you off to Zen'tabra to begin your training.
Zen'Tabra likes to start things simply, so she'll help you cover The Basics: Hitting Things. All around the Darkspear training grounds are tiki-themed target dummies. Blow up six of them, using your favorite method for blowing up stuff. After this impressive display to skill, you're off to A Rough Start and have to go kill enough cats to bring Zen'Tabra six Wildmane Cat Pelts. Go kill some kitties. If the starting area is busy, it can take a while to find enough cats, so take your time.
Once you've pelted Zen'tabra (get it?), she sends you to the Proving Pit. Speak to the Darkspear Jailor to release a naga into the pit. Go kill it. After some class-specific training to be sure you know how to use your buttons, you'll be sent to the big man himself: Vol'jin!
When you turn in the quest, you get the opportunity to see the much-discussed argument between Garrosh and Vol'jin. This is the argument that sets much of the tone for the Horde in Cataclysm. It's also a great opportunity for you to see just how bloody awesome Vol'jin really is.
Vol'jin welcomes you among the heroes of the Darkspear but sends you off to find Moraya. She's been needing some help with the raptors, apparently. Moraya is to the east of Vol'jin's hut, and you can grab a quest to go Crab Fishin' on your way out. When you speak with Moraya, she actually sends you to the south of the island to help move A Troll's Truest Companion. (Trolls feel the same way about their raptors that humans do about their labrador retrievers.)
Now is the time to complete these two quests. Go directly south of Moraya and down the hill. Lots of Pygmy Surf Crawlers hang out there, and they're an easy kill for Crab Fishin'. Then go back up the hill and angle to the west to cross the big bridge. As you start moving across the bridge, a troll named Zuni will ask you to wait up for him. He'll be your companion for a short time.
When you arrive at the southern island, there are a few more crabs around, in case you're missing any. Talk to Kijara in the center of the island. Her first priority is Saving the Young. Swim northwest to the next island over. (There is no bridge.) Find the hatchlings, and use the whistle given to you. The little fellows will start following you. Once you've gathered up 12 of the hatchlings, head back to Kijara. Take the time to enjoy the cutest little army ever created following you.
Tegashi now has a pair of tasks for you. Show some Mercy for the Lost by going back to the island and killing Corrupted Bloodtalons. Once you've done that, climb the hill in the center to kill Naj'tess. If there are other players where Naj'tess spawns, you may need to wait to get a chance to kill him yourself. This is just what it takes to defeat the Consort of the Sea Witch. He might shrink you as you fight him; don't worry, you'll be fine.
Return to Tegashi and Kijara. Kijara tells you it's time to handle the Young and Vicious raptor known as Swiftclaw. He looks unique from the other raptors on the island and has been doing laps the whole time you've been around. Once you see him come rushing near you, use the lasso. Suddenly, you're riding Swiftclaw!
Ride him all the way back to the pens on the main island. As you enter the pens, you will be automatically dismounted. Return to Moraya, who is still chilling on her mat near Vol'jin. Now is also a good time to turn in the crab meat to Tora'jin. Once you've done both, go to Tortunga, who has the next important quest for you.
Tortunga tells you it's time to lay some troll vengeance down on the naga. Speaking to Jornun will get you a quick raptor ride up to the front line. Morakki accepts your quest and gives you orders to provide the naga No More Mercy and to place Territorial Fetishes on the Spitescale flags. Enter the cave and kill 12 naga, using the fetish in your backpack to complete the other quest. Zuni is back to hang out with you during this portion.
The fetishes require the Spitescale flags. Essentially, you're placing the troll fetish over top the flag. Keep an eye out for them as you wander around. Also, Zuni is a little crazy. He will wander off frequently. So he's helpful, but don't rely on him. When you turn in these quests, Morakki will send you to slay An Ancient Enemy, the Sea Witch herself.
Go around to the northeast of the island and speak with Vol'jin to start the combat. Kill the little ghosts that pop up, but try and avoid fighting the Sea Witch herself. She's a big, big mob and is meant for Vol'jin to fight. If the fight is already in progress, help out by fighting the ghosts; you'll still get quest credit. Speaking with Vanira will teleport you back to Darkspear Hold.
When you talk to Vol'jin to turn in An Ancient Enemy, you get to be present while Vol'jin and Thrall have a chat. It's a fairly impressive conversation in which Thrall says that he hopes Garrosh's true blood will inspire the Horde. After this discussion, you are sent to Sen'jin Village. You can find it by leaving Echo Islands west and traveling across the water.
This begins your experience with the main world of Azeroth, and it means you have successfully completed the Horde starting area.
Visit the WoW Rookie Guide for links to everything you need to get started as a new player, from how to control your character and camera angles when you're just starting out, to pulling together enough cash for mid-level expenses such as mounts and dual specialization, to what to do when you finally hit level 80.