Heroic Cataclysm dungeons require an overall minimum average item level of 329 before you can queue for them in the World of Warcraft dungeon finder. While practice running these dungeons cannot be underestimated, here are five ways to obtain plenty of item level 333 blue gear that you'll need before you can queue for heroics.
Regular Mode Dungeons
Bosses in regular mode Lost City of the Tol'vir, Grim Batol, and Halls of Origination will drop ilvl 333 blues. Additionally, completing dungeon quests will give you more blue items to choose from. Running random regular mode dungeons is also a great way to start accumulating justice points to redeem for heroic level ilvl 346 gear.
Completing all of the quest lines in Uldum and Twilight Highlands will provide many blue items to add to your gear arsenal. Questing is also an extremely easy way to build your reputation with several factions.
Raising your reputation with all of the Cataclysm factions can help you get several pieces of high level gear. Quests alone will get you honored with Guardians of Hyjal, Ramkahen, Therazane, The Earthen Ring, and Wildhammer (or Dragonmaw). At honored you have access to ilevel 333 blues; revered gets you ilvl 346 blues; and exalted will give you access to ilvl 359 epics. As soon as you're friendly with each of these factions, you can purchase a tabard to wear in dungeons for additional reputation gains.
Crafted items can help fill in the holes in your collection of gear. If you are able to collect the materials and find someone to craft them, this will often be cheaper than purchasing them outright on the auction house. Use caution when purchasing ilvl 339 PvP items to help raise your item level, as the overall stats will be weaker for PvE. (This is mostly only an issue for tanks.)
Bind on Equip World Drops
If you've got gold to spend, BoE items are a quick way to upgrade your gear – but they can sometimes come with a hefty price tag. If you don't mind parting with the coin, BoE items from the auction house provide a fast way to get your character ready for heroic dungeons gear-wise.
Item Level Is Only The Beginning
Once you've reached the minimum item level of 329, make sure to get gems and enchants for your gear. Even cheap ones are better than none. But most importantly, make sure to familiarize yourself with the dungeon strategies. This can be accomplished by practicing them on normal mode (with the exception of Deadmines and Shadowfang Keep) and watching videos on sites like TankSpot.