So I set out on a mission to help my friends make some more gold, and I ended up putting together a guide just for them to be able to reference with some tips and pointers that people of all levels could benefit from, and quite a few of them started making hundreds of gold every week.
As I said above, yes, always use a buy-it-now. The next question is to price the buy-it-now the same, lower, or more than the other items on the Auction House. I have the Auctioneer add-on, which tells me what the market price is for items on my server. I recommend getting this add-on and pricing at the market price, because most of the time your item will sell on the first try. If you don't have Auctioneer, look at how the items currently on the Auction House are priced. If there is only one screen of items, price yours the same as the others.
If you are going to use this method, look for an add-on called Auctioneer. Auctioneer will scan the auction house for low priced items, so you don't even have to spend time hunting through the category tree. Auctioneer keeps track of the average selling price of items, so you will know if something is way underpriced and can be bought low and sold high. You can even park a low level alt by the auction house with a couple of gold to run your scans and buy cheap items, so your main character doesn't have to come back from grinding or questing.
I would suggest starting with two gathering professions. For one of the professions, consider skinning. The reason I say this is because when your farming, a lot of times you can skin who your killing which is double the payout. For example if you farm devilsaurs, their leather can sell up to 50 gold per stack. Mining tends to get pretty competitive but at the same time it has the potential to be very lucrative. Herbalism is a solid profession to have because you can quickly gather herbs that is demand.
It's a lot easier to purchase gold on World Of Warcraft than to farm for it. MMOG sites have a full inventory and also sell other useful items to enhance your character.
Now to amplify this strategy you want to do it to meet your servers needs. You should recognize your server needs each day when you make your AH scans. You mainly want to check the Cloth and low level armor/weapons. If you see a big level gap missing or one major section of cloth missing, this is exactly what you want to target. By missing I mean they aren't existent in the AH at the time you look for it, or you will see that there's a few auctions but they are crazily inflated (like linen popping in for 2g, or low level items for 5-6g).