Introduction
Hello and welcome, if you're on the Alliance side, this will probably be your first instance. If you're on the Horde side then you must be really bored/determined.
There are four total quests for the Deadmines, however I will not include them with the guide, I'm just simply listing them if you wish to do them.
Collecting Memories http://wow.allakhazam.com/db/quest.html?wquest=168
Oh Brother... http://wow.allakhazam.com/db/quest.html?wquest=167
The Defias Brotherhood http://wow.allakhazam.com/db/quest.html?wquest=166
Underground Assault http://wow.allakhazam.com/db/quest.html?wquest=2040
To start, the Deadmines are located in the south side of the Westfall region inside the abanoned town called Moonbrook. To get there simply go in the barn on the Southwest side of the town and follow the map to the instance gate. Inside the barn on the way to the instance there will be Miners along the walls and the occasional Elites partolling the area. Nothing to worry about simply clear them out little by little and make your way to the gate. Once through the gate, it's basically the same thing as outside as you make your way to the first boss.
---Note: There are no respawns here with one exception, patrol groups. They're usually group one to three elites most commonly spawned a few minutes after an area has been cleared. However once you get to the ship they stop spawning in that area and beyond, you'll only find them back where you wouldn't pass through unless a party member died and couldn't be resurrected.
Boss #1: Rhahk'Zor the Foreman http://wow.allakhazam.com/db/mob.html?wmob=644
Alright, Rhahk'Zor is in a roughly 15x15 room and paces back and forth from the back doors to the entrance. He is accompanied by two Defias Taskmaster, Elite that use ranged attacks. If you wait long enough for him to come close to the entrance you can usually pull him without drawing the attention of his two Taskmasters. As for Rhahk'Zor himself he's a pushover. Very slow attack speed combined with horrible accuracy makes this an easy battle, the only thing he may have aside from other elites is a large amount of HP. Unfortunately he has no bind on pickup items to get.
Rare Spawn: Miner Johnson http://wow.allakhazam.com/db/mob.html?wmob=3586
This sub boss is located in the left path right past Rhahk'zor's room and is -not- always going to be there. Only a handful of miners are in your way. No special strategies needed for him. He has two bind on pickup items.
Gold-plated Buckler http://wow.allakhazam.com/db/item.html?witem=5443
Miner's Cape http://wow.allakhazam.com/db/item.html?witem=5444
Boss #2: Sneed the Taskmaster http://wow.allakhazam.com/db/mob.html?wmob=643 ...and his Shredder http://wow.allakhazam.com/db/mob.html?wmob=642
Continuing south from the intersection after Rhahk'Zor brings you to the second boss. The Shredder paces up and down the ramp collecting wood, while it goes up the ramp quickly pull goblins out of the room and dispose of them. Once they're all dead you're ready to take down the Shredder. The Shredder has high accuracy and fast attacks but has low damage. Nothing else noteable about it. It drops one bind on pickup item.
Buzz Saw http://wow.allakhazam.com/db/item.html?witem=1937
After the Shredder falls Sneed jumps out at the last moment, too bad for him he's only as strong as the other goblins you just killed. He drops two bind on pickup items.
Taskmaster Axe http://wow.allakhazam.com/db/item.html?witem=5194
Gold-flecked Gloves http://wow.allakhazam.com/db/item.html?witem=5195
Boss #3: Glind the Smelter http://wow.allakhazam.com/db/mob.html?wmob=1763
Alright now, this room is a living hell for pullers. One wrong move and you now have five Elites after you, several of which are spawning remote controul robots to fight with them which are also elite. I suggest moving everyone down the spiral ramp very slowly mob after mob and having one person pulling from about 20m ahead of everyone else. Once you get to the bottom, stop. Have the puller run back past the party when pulling Engineers since they use ranged attacks, these are also the ones with the Robots so watch for them spawning any mid battle. Craftsmen are just really weak mages that like to use a DoT fire AoE, nothing strong enough to worry about. After the room is clear, guarding the exit in Glind. Just like Sneed I noticed no differences between him and other Goblins. I guess you would say navigating down the room is more or less the enemy than him. He drops two bind on pickup items.
Lavishly Jeweled Ring http://wow.allakhazam.com/db/item.html?witem=1156
Smelting Pants http://wow.allakhazam.com/db/item.html?witem=5199
Boss #4: Mr. Smite the Ship's First Mate http://wow.allakhazam.com/db/mob.html?wmob=646
Moving along, we come to the ship. Make your way through the Pirates and Squallshapers until you come to a small rock island. Up the ramp connected to the island is Mr. Smite. There's a very important strategy to go with this battle so pay attention. When you pull him, fight him right next to the chest on the side and kill his two Blackguards first. I cannot stress this enough. The reason being once Smite loses a certain amount of HP he stuns the whole party while he runs to the chest and changes weapons. Meanwhile his Blackguards are free to attack your stunned party while he does it. Twice a battle he stuns so taking out the Blackguard is of vital importance. As for Smite himself, he starts with an axe, switches to dual weilding, then switches to a two-handed mace. Damage is consistent and he has a lot of HP so be careful of keeping the tank alive. He drops three bind on pickup items.
Smite's Mighty Hammer http://wow.allakhazam.com/db/item.html?witem=7230
Smite's Reaver http://wow.allakhazam.com/db/item.html?witem=5196
Thief's Blade http://wow.allakhazam.com/db/item.html?witem=5192
Boss #5: Cookie the Ship's Cook http://wow.allakhazam.com/db/mob.html?wmob=645
Going left at the top of the ramp where Smite once stood you'll find Cookie. A pretty normal mob with one exception, she uses a horrible AoE that does a lot of damage over time. Have your Priests/Druids ready to remove diseases from the tanks. She drops two bind on pickup items.
Cookie's Stirring Rod http://wow.allakhazam.com/db/item.html?witem=5198
Cookie's Tenderizer http://wow.allakhazam.com/db/item.html?witem=5197
Boss #6: Captain Greenskin http://wow.allakhazam.com/dyn/mobs/zone68.html
Backtracking and going right of the ramp brings you to another ramp. Move the party up to the second loft and keep them there. Have your puller slowly go further up the ramp. Greenskin does laps around the deck and can aggro if he passes by you while going up the ramp bringing six or so other Elites with him. Pull one mob at a time and run down the ramp when you get a chance. Once it's clear pull down Greenskin and his two guards. Since they're just a normal Pirate and Squallstopper I advise killing Greenskin first. High accuracy and damage but a low attack speed and normal HP make this a pretty average battle. No special attacks or events here. He drops two bind on pickup items.
Emberstone Staff http://wow.allakhazam.com/db/item.html?witem=5201
Impaling Harpoon http://wow.allakhazam.com/db/item.html?witem=5200
Final Instance Boss: Edwin VanCleef the Defias Kingpin http://wow.allakhazam.com/db/mob.html?wmob=639
After all of that it's almost over. It's finally time to go head to head with VanCleef. He stays in the shed ontop of the ship until someone either uses a ranged attack or enters the shed itself. To start the battle, he calls two Blackguards. Kill these first then attack VanCleef. At about 50% HP he'll call two more Blackguards to fight. This is why you took out the first two. But now since it's just a choice between them or him you might as well take him down now. He has a lot of HP, great accuracy, and fast attack speed from dual weilding two scimitars. It's a touch battle but you should be able to make it. He drops four bind on pickup items.
Blackened Defias Armour http://wow.allakhazam.com/db/item.html?witem=10399
Cape of the Brotherhood http://wow.allakhazam.com/db/item.html?witem=5193
Corsair's Overshirt http://wow.allakhazam.com/db/item.html?witem=5202
Cruel Barb http://wow.allakhazam.com/db/item.html?witem=5191
To exit, simply jump off the east side of the ship and go through the tunnel up the hill.