Auctioneer is your friend.
Not to sound vain, but in response to the topic ... before I reached lvl40 (my 1st char - only been playing WoW for about 2 weeks now) over the weekend I've already made over 1k of gold. A great deal of it was through selling ore, but if you play it right you can make $ for jam. By the end of the same day that I bought my 1st mount I had already made back the gold I used to buy it.
Be careful when playing the AH though ... 1) you can upset the economy. Ludicrous prices spoil it for everyone. 2) If its too good to be true, it probably is... I sold my first sparkling azure moonstone for 16g within hours of auctioning it off. I then went and 'procured' 15 more of them. I've been struggling to sell them ever since. I'm currently bidding them off at below 3g, just to get rid of them because they're taking up space for items/stacks that will reach far better prices.
Do yourself a favour and take on gathering professions until you're high enough. As my one mate said "there are faaar too many animals roaming around to ignore".
Lastly - gold isn't everything, if you spend all your time trying to make gold you'll lose sight of the game. And besides, once you hit lvl 70 you'll make more gold than you care for - and the use of gold is pretty pointless since all you're after is honour points for epic gear anyway.
