The WF/TF system complicates gearing a bit, as you could get an Uncommon quest reward that forges to Epic quality (not a myth - it happened to me on the first night of release). This means that the old ‘Best in Slot' system is, to all intents and purposes, useless, and you should generally opt for whatever item you have that is the highest level - especially as tier gear no longer exists.
The leveling guides on my site are essentially speed leveling guides.  My leveling guides are the same guides I use myself to speedrun to 60 on new servers to get 60 server first.  I list many occasions where I tell the player to "die on purpose" to go faster.  I tell the player to skip certain quests, because some quests are just not worth the time/XP.  I list tricks and shortcuts to go faster so you can reach level 60 much quicker.  I am still constantly going through them over and over again perfecting the guides to make them faster and easier to follow.  For the most part, the guide can be followed without the need from other player's help, as the whole guide was made from a solo run anyways.  Although I do list quests that can optionally be done if you have a group.
How is this better than the in-game quest helper thingie? While that shows you the destination of your quests it doesn’t show you the best order in which to take them, which to skip, and when to move on (such as when you’ve out leveled the area.) .  Zygor’s show you the optimum path to take to complete the most quests in the least time, which will save you lots of time over the quest helper.
Buffs. Food/Flasks/Scrolls/Potions/Elixirs are a small, but noticeable, buff to your killing speed and survivability. If you have a max level character that can already supply you with cooking or alchemy, you'll be very well off, because the AH is a cesspool for this. I can't really give you specific foods or potions to look for, since each AH is going to have different supplies. Generally speaking, lower level foods are going to only last 15-20 minutes until you can buy the more powerful versions at 60+. Look for anything that adds versatility or your primary stat, and buy stacks for each level range(1-60/70/80/90/100).
I do not recommend going for TBC, although I remember Hellfire peninsula to be decent, everything else is rather slow. Instead go for WotLK, Borean Thundra gets you levelled very fast, and then you can head straight for Icecrown at 67, which is also insanely fast, although admittedly has a few elite quests. You can go to Sholazar Basin alternatively. 2 zones should get you 60-80 no problem.
 Lightforged draenei - "For untold millennia, the Army of the Light waged war against the Burning Legion throughout the Twisting Nether. The draenei most committed to their long crusade would undergo a ritual to become Lightforged, infusing their bodies with the very essence of the Holy Light. After finally achieving victory on Argus, the Lightforged Draenei have undertaken a new mission: protecting Azeroth from rising threats and helping the Alliance push back against Horde aggression."

In addition, you'll want to pick up leg and shoulder enchants and have them in your bags. These enchants have a level requirement of 80/85, but can't be placed on items above iLVL 136. You can get around this by having a level 85-100 character apply the enchant before mailing it to the character you're leveling, thus getting use of the enchants before level 85. I've personally confirmed that this works.
Level with a pet if you can because it will help keep you safe. If your pet is tanking all of the damage from the enemies you’re fighting, you won’t have to. The other reason is that pets are easier and cheaper to heal than you are. If you don’t have a pet, make sure you know how to use your defensive abilities. You can’t level quickly if you are dying all the time.
Engineering has the option at skill level 200 to specialize in Gnomish or Goblin Engineering. You can get the quests from your Engineering trainer. The main difference between both sides is the location of their respective teleporters and the ability of their trinkets. Some items require a specific specialization to use, while other items are crafted by one specialization but are usable by any engineer. Fortunately, most recipes that are crafted by one Specialization can be worn by both.
No matter your experience level—whether you’re about to experience the thrill of hearing the Stormwind City theme as you walk through its epic gates for the first time, or whether you can spell Ahn’Qiraj off the top of your head—here are some tips and suggestions for making the most of your new life in the World of Warcraft (or your epic, Illidan-like return to Azeroth.)
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