Twinking can enable a level 15 character, for example, to take on mobs of levels 20 or higher with impunity and thus gain more experience with each kill. More mobs at a higher level equates to faster levelling.
Also in the EPL, Carrion Grubs and Carrion Devourers have a high drop rate for Laval acid, which can fetch up to 7 WoW Gold!
It even comes with a bonus gold guide. The gold guide is not that thorough at all, but it does offer some great beginner tips to get you pointed the right direction.
If you have let us say 10,000 g and you already have the epic mount and the coolest gear a lot of players will start to look up to you. This way you could let them join you and teach them your tricks. The will most likely tell friends about you and soon you will be in a great position. Most gold guides give you complete auction house strategies and this is one of the best kept secrets.
Humanoids tend to drop items such as cloth and wool. You generally won't find those items on say a bear or spider. So depending on what you are collecting will dictate what you kill.
Spend the gold to respec your character to the best grinding spec. Every class has one, and it is worth the investment to go out and do if you plan on farming for gold in World of Warcraft.
Fishing - this used to be effective in the past. But things come, and go, and come and go again. Who knows when fishing may become useful again? Just something for you to keep in mind.
So should you visit Area 52, take care in the trinkets that you purchase - especially, the Dimensional Ripper - Area 52, which, if you take my advice, you'll sell it on the Auction House for at least 300g and avoid the embarrassment of possibly a hyper-dimensional sex change.
Armor or gear and weapons in the game will be your biggest expense so at the low levels 1-30 do not get to obsessed with your gear as you will need the gold later on to get the good gear so you can do some of the end game raids to get the awesome gear that gold will not buy you.
By using this method, they can quickly and easily get rid of 200 or more silk cloths and get out of the Auction House with a 40% boost in sales by artificially inflating prices.