This post is mostly random anecdote, but I do believe it is illustrative of a part of gold making that can have a significant impact: Luck.
So I'm at the AH, going through my regular routine, when I see in trade chat that someone has just posted 66 stacks of Obsidium Ore for 50g a stack. Now I don't know about anyone else's server, but mine is experiencing a dearth of cheap Obsidium. For whatever reason - bots being banned, Ore Crusher alerting JCs to the awesomeness of prospecting, lazy farmers, etc. - it has been quite rare for the past few weeks for Obsidium Ore to be posted below 70g, and often there's a huge shortage, with some stacks even up to around 100g. Try as I might, I've yet to snag a dependable farmer (the one I had seems to have stopped farming...), and unlike some people I didn't buy up G-Bank tabs full of Ore (a lack of foresight on my part, I guess), so 66 stacks at 50g seemed like a godsend. Sure enough, there they were, and I managed to buy up every single one. I sent the seller a tell too, and it turns out that someone had hacked his account and used it for botting, and when it was recovered he was left with an extraordinary amount of ore and wanted to syphon some of it off. He's currently keeping some to level his engineering back up, but he has agreed to send me any leftovers he has.
So what's the point of all this? Simply that being lucky can pay off big time. To elaborate, this is why we have things like snatch lists. (Or at least, we probably should. That's an area I really need to work on) Being able to spot good deals is a key skill all goblins should have, but it's something that really only comes through experience. 50g per stack of ore may seem to be an obvious deal, but that's only because we know of the 54g "floor price." Other examples from my past include things like a 2k Parrot Cage (Hyacinth Macaw), or Hurricane Decks for 10k. So be sure to keep up with gold blogs and patch notes, and keep an eye on your server's prices, because you never know when someone will be selling something for cheap, and you won't know that it's cheap unless you know what it's really worth!
And to make this post a bit more interactive, please share what the best deal you've snagged or are currently snatching!