There are a few ways i would recommend. First is the Darkmoon Faire, which rotates monthly. Look up online when it next comes near. The two vendors there sell rare items very cheap, although you will need to camp out there and keep checking as they change what they sell every 5 mins or so. I started as a NE Hunter with ~12G and in one Darkmoon Faire i made 1000G selling the stuff i bought on AH. I would advise that first.
Next i would try and join a guild, look for a 'fun' guild not a rading one. Ask very nicely if you could get a run through of low level instances e.g Deadmines. You'll get some good XP, some nice loot to sell, and some great gear for your level.
You could also try taking two harvesting skill, i.e Mining + Skinning, which will give the most money when you sell the items. Although of course you won't be able to create any nice gear for yourself, without a creating skil e.g Leatheroworking
Finally you could try and play the Auction House. "Buy low, sell high". There are plenty of guides on the net for free about this. Basically get the add on Auctioneer or WoWecon and let it scan for a few days to get an idea of what things sell for (You don't have to have these add ons, but they help) then if you see something selling for much cheaper than its worth buy it, then put it back on to sell for morel. I don't like this technique too much as there is high risk involved, unlike the others.
If you want to try to go to the Darkmoon Faire, it starts on the 7th July 08 in Mulgore (Horde Territory) and i will be heading there, so if you are on Dragonmaw (EU) by any chance send a whisp to Audere
Hope this helps.
One final tip. Don't worry so muich about gear and stuff when you are so low levelled. You will outbrow it before you even realise you are wearing it! Wait til 60+ before you start working hard for gear.
Ed