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.
Through out the game, the quest log will be capped to 20 many times. The guide makes use of maximizing the total amount of quests you can accept at once. Because of this it is important to follow the guide exactly and only accept quests if the guide tells you to so you won't run into issues not being able to accept a quest. If you do accept a quest that is not listed in the guide, write it down because you may need to abandon it in order to keep following the guide if your quest log is full.
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).
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).