Among many things is getting good gear to enter Karazhan. To get the right gear you should be 100% sure you know your class and able to use all roles like : healing, main tanking, off tanking, crowd control, damage, more damage, more and more damage .

The easiest way to do so is to do a looot of instances. After reaching lvl 70 you need to get the Heroic keys, in the way you may get a Dungeon Set 3 if possible on non heroic instances. here is a list of following sets, click on the items to see stats, and where to get them.

Be aware this items are not class restricted, you need to thing over what is better for you, combine set for better stats and loose the bonuses or the other way around.

Rogue.
Assassination Armor
Handgrips of Assassination - The Black Morass (Caverns of Time) - Aeonus
Helm of Assassination - The Arcatraz (Tempest Keep) - Harbinger Skyriss
Leggings of Assassination - Shadow Labyrinth (Auchindoun) - Murmur
Shoulderpads of Assassination - Sethekk Halls (Auchindoun) - Talon King Ikiss
Tunic of Assassination - The Mechanar (Tempest Keep) - Pathaleon the Calculator

Druid - Rogue.
Wastewalker Armor
Tunic Drops from: The Blood Furnace (Heroic), Keli'dan the Breaker
Gloves Drop from: The Shattered Halls (Normal & Heroic), Warchief Kargath Bladefist
Helm Drops from: Old Hillsbrad Foothills (Heroic), Epoch Hunter
Leggings Drop from: Mana-Tombs (Heroic), Nexus-Prince Shaffar
Shoulders Drop from: Auchenai Crypts (Heroic), Avatar of the Martyred

Druid.
Moonglade Raiment
Head: The Botanica
Gloves: Shadow Labyrinth
Pants: The Black Morass
Chest: The Mechanar
Shoulders: The Steamvault

Warrior.
Bold Armor
Chest plate - Harbringer Skyriss, (Arcatraz).
Gauntelts - Warlord Kalithresh, (Steamvault).
Legplates - Aeonus, (Black Morass).
Shoulders - Murmur (Shadow Labyrinth).
Head - Warp Splinter (Botanica).

Warrior - Paladin.
Doomplate Battlegear
Doomplate Chestguard >> Harbinger Skyriss at The Arcatraz
Doomplate Gauntlets >> Keli'dan the Breaker at The Blood Furnace
Doomplate Warhelm >> Epoch Hunter at Old Hillsbrad Foothills
Doomplate Legguards >> Exarch Maladaar at Auchenai Crypts
Doomplate Shoulderguards >> The Black Stalker at The Underbog

Paladin.
Righteous Armor
- Breastplate from Warlord Kalithresh, Steamvault, Coilfang Reservoir
- Gauntlets from Warchief Kargath Bladefist, Shattered Halls, Hellfire Citadel
- Helm from Pathaleon the Calculator, Mechanar, Tempest Keep
- Legplates from Aeonus, Black Morass, Caverns of Time
- Spaulders from Laj, Botanica, Tempest Keep

Hunter.
Beast Lord Armor
Beast Lord Curiass:Warp Splinter - The Botanica
Beast Lord Handguards:Warchief Kargath Bladefist - The Shattered Halls
Beast Lord Helm:Pathaleon the Calculator - The Mechanar
Beast Lord Leggings:Warlord Kalithresh - The Steamvault
Beast Lord Mantle:Warlord Kalithresh - The Steamvault

Hunter - Shaman.
Desolation Battlegear
Gloves: Shattered Halls(HC), Warchief Kargath Bladefist
Legs: Sethekk Halls(Auch), Talon King Ikiss
Chest: Old Hillsbrad(CoT), Epoch Hunter (heroic mode)
Head: The Black Morass(CoT), Aeonus
Shoulders: Slave Pens (CFR), Quagmirran (heroic mode)

Shaman.
Tidefury Raiment
Warp Splinter, Botanica (Helm)
Warbringer O'mrogg, Shattered Halls (Shoulders)
Harbinger Skyriss, Arcatraz (Chest)
Warlord Kalithresh, Steamvault (Hands)
Murmur, Shadow Labyrinth (Legs)Last edited by

Priest.
Hallowed Raiment
Sethekk Halls - Talon King Ikiss - Pants
Shattered Halls - Kargath Bladefist - Hands
Shadow Labs - Vorpil - Shoulders
Shadow Labs - Murmur - Chest
Arcatraz - Harbinger Skyriss - Head

Priest - Mage.
Mana-Etched Regalia
Aeonus - The Black Morass - Head
Omor the Unscarred - Hellfire Ramparts - Gloves (Heroic)
The Black Stalker - The Underbog - Pants (Heroic)
Epoch Hunter - Old Hillsbrad Foothills - Robe (Heroic)
Quagmirran - The Slave Pens - Shoulders (Heroic)

Mage.
Incanter's Regalia
Head - Mechanar - Pathaleon
Gloves - Steamvault - Hydromancer Thespia
Shoulders - Steamvault - Warlord Kalithresh
Chest - Botanica - Warp Splinter
Legs - Sethekk Halls - Talon King Ikiss

Warlock.
Oblivion Raiment
Sethekk Halls - Talon King Ikiss - Pants
Shattered Halls - Kargath Bladefist - Hands
Shadow Labs - Murmer - Shoulders
Shadow Labs - Murmur - Chest
Arcatraz - Harbinger Skyriss - Head