I like his recommendations 2 level 1-20 zones to get to 20, then do all the 2nd zones since they are designed for walking (Horde: Northern Barrens, Silverpine Forest, Ghostlands, Azshara, & Hillsbrad Foothills if you need a little more. Alliance: Westfall, Loch Modan, Darkshore, Bloodmyst Isle, and if you need a little more Redridge Mtns, or Duskwood). Don't even bother with the higher level areas, too spread out. Finishing up a Monk now and I had done all these zones before the update, the running between quest and the 50% experience cap is driving me crazy.
Picking up herbalism and mining is the best professions to have while leveling. Not only will you earn gold as you level, but you will also get extra XP. At level 20 you will get over 500 XP for picking up a ore or a herb while killing a mob only gives a little over 100 XP. Don’t go out of your way to pick herbs if you are trying to level quickly, but pick the ones that are on your way. Leveling from 110 to 120 can be done pretty quickly just by doing this. There are a few items that will help you if you decide to use professions while leveling:
Mag'har Orc Allied Race Leveling Guide (20-120) Dark Iron Dwarf Allied Race Leveling Guide (20-120) Void Elf Allied Race Leveling Guide (20-120) Best Void Elf Allied Race specs for leveling, efficient zones to level in, and overview of available classes and level 20 starting abilities. Level a Void Elf to 110 for a special set of cosmetic Heritage Armor. Nightborne Allied Race Leveling Guide (20-120) Best Nightborne Allied Race specs for leveling, efficient zones to level in, and overview of available classes and level 20 starting abilities. Level a Nightborne to 110 for a special set of cosmetic Heritage Armor.