Take up skinning and mining for wow gold. Skin everything you kill, mine everything you can and just sell it on the auction house. It'll add up over time. Also anything in white/green/blue letters sells on the auction house usually. Download an add-on called auctioneer for you, it will help a lot in making wow gold.

What I did was clear all quests in every zone in northend, and skinning and herbalism or mining, clear the quests will not take you too much time, when you cleared 3 or 4 zones you will probably have 6,000 wow gold with you, then that is enough for an epic flying mount. Meaning, don't take the “go here, then go here, then go here then go here” quests. Take the “go kill me 10 of those spiders you were going to kill anyways” kind of quests. Kill the 10 spiders, kill 30 more, when you get bored or need to sell, go turn the quest in.

Take quests that are on your way making wow gold. A good pair of professions is mining and skinning or herbalism. For leveling really fast, kill stuff there is a large supply of and kill it as fast as possible. Mining supports blacksmiths, jewelcrafters, and engineers so it hits a nice margin. Another thing to do is scan the auction house for items that are being sold at a really low price, buy it, then turn around and mark the price up.