BOOOM Finally hit the goldcap yesterday afternoon! Took me almost exactly 4 months to do.
Started with 3k and a 450 jewelcrafter with a few epic cuts. During these 4 months I've powerleveled inscription and a xmute alchemist (and I've got the mats to finish enchanting if I can just level the dude 4 more stinking levels lol). Other than that, I didn't do any spending other than raw mats.
A couple of things I picked up along the way:
1. Diversify. Even if you've got a surefire moneymaker (like, cardinal rubies made up half of my revenue) you're going to have dry spells...either some idiot posts below your threshold for a week, or you run out of mats for days (both happened to me several times!). You need to be able to have your fingers in different pies to smooth out the income flow.
2. Dominate. Although it helps do diversify, for every market you get into you need to have the mindset of "I'm going to own these bitches". Don't go in half ass. Part of my success was I smothered the market...I drove quite a few competitors out because I pretty much completely cut off their sales. Be prepared to make enemies, but be professional (or even better, be quiet!)
3. Never stop buying mats. If the price is good, buy it. Otherwise, it's guaranteed that some day there will be lot of sales and you will run out of mats. Find suppliers and keep them on your friends list. Remind them all the time that you're buying. Be friendly and courteous when talking to suppliers.
I'd like to thank everyone on these forums, and also the website wowconfidential.com. Between those two I learned how to set up and configure addons that really make the difference, and picked up on some really insightful tips that have helped pad my revenue considerably.
Not going for 500K or anything like that...goldcap is plenty fine for me! My goal is to continue making money, maintain above 200K in the bank, and start preparing for Cataclysm (buying Portable Holes for my main characters, profession "leveling kits" for my goblin, maybe some decent BoE levelling gear, etc)...and of course, building up a stockpile of mats to resell once the xpac hits!