Swim Speed Potions (used especially at lvl 37 for Faldir's Cove in Arathi Highlands and lvl 57 in WPL). Try to get multiple stacks of these. I also recommend keeping a stack of these always in your bags. You will frequently pass rivers and lakes and can use these potions to pass them faster through out the guide. Please note that these potions do not stack with Druid's Aquatic Form and Glyph of Aquatic Form.
Pick the Right Professions - Professions will amount to a very large portion of your Gold income if you pick the right ones. We will cover this subject in much more detail in the next section of this Guide, but here is a TL/DR version: Gathering Professions are generally better on new servers (for example, Skinning provides you with some extra money for every single Beast that you slay in the world, even if you just vendor the gathered Leather), especially if you are leveling quickly, as Crafting professions require a lot of Time and Gold investment to level up (but they get much better when you are leveling slowly and during the End-Game, because then the ability to craft some gear starts to outvalue the ability to make a quick profit).
If possible, avoid purchasing Gear from the Auction House - Ideally, you should be able to achieve level 60 without buying anything from the Auction House. This way you will save Gold, but possibly make leveling a bit harder for yourself. If you badly require an Item upgrade, and the suitable Item is available on the Auction House for a low enough price - buy it, but only if you think that the investment will pay for itself in one way or another (the main exceptions to the Auction House ban Rule are Weapons and Wands, as they make leveling much faster, and pay for themselves by allowing you to chain-kill more mobs without Eating and Drinking, which saves Gold and time).
Nov 15 My only complain about Classic... ...Horde doesn't have any nice looking races. In my mind each class has best RPG based race for it. So, I like Gnomes because I feel them Mages. Night Elves - Hunters. Humans - Paladins. On Horde side: Undead - ugly. Trolls - ugly. Orcs... uhh fine as Warriors, but I don't play warriors. Tauren - Warriors or Shaman, again don't play those. Blood Elves! Give me Blood Elves!Vlasta36 Nov 15
Check Item's Vendor Price before posting it on the Auction House - Selling items on the Auction House below their Vendor value is a common mistake. Avoid it like fire, and always make sure that you are not losing Gold on your Auctions. If you plan to sell an item on the AH for a price just a tiny bit higher than its Vendor value, you might be better off just vendoring the said item (this will allow you to avoid the risk of losing an Auction fee if your Item doesn't sell).