Although these topics have been covered in greater depth (and quality) elsewhere, here's a very brief overview of some basics as I get the ball rolling on The Real Quaaid.
Probably the single most important factor in streamlining gold making is the use of addons. I'm not particularly adept at such matters, but the following are extremely useful (if not quite mandatory):
Just my two copper - this site, and its forums, are the impetus for this blog. Fascinating posts, good insight, and an extremely intelligent community.
Phase 3 Profit - Frequently updated, with some good tips and overall good flow.
Greedy Goblin - not an egalitarian bone in this guy's body, I love the pithy tone.
It cannot be said often enough, "time is money, friend." The one thing I loathe about many gold capped bloggers is how they reference doing AH scans multiple times a day, posting/reposting, and crafting for hours. My attitude is, get in, do your crafting/posting efficiently and with a minimum of frequency possible, and get out. I post auctions once a day -- if that -- and do batch crafting maybe once a week, and for some items less frequently than that. Bragging about being gold capped is fruitless when it's a part-time job.
In other words, work smarter and not harder.
How not to do it:
Spamming trade must be the greatest detriment to profiteering possible. If you spam trade like these players below, you'll never get anywhere...it's fighting for tips, which is basically no margin, and your competition is in plain sight. I generally ignore trade channel, except to sometimes find tailors, leatherworkers, etc. (professions I don't have access to) to craft items. I'll buy the mats on the AH, tip them 10g for a combine, and post the finished product on the AH...usually with at least 50% margin. That could've been theirs.
Volume vs. margin
A legitimate, healthy debate can be had between those who prefer quantity (i.e., a high volume of sales at ostensibly low margins) versus quality (i.e., infrequent sales at much higher margins). I was formerly in the latter camp, but have come around a bit to the former. I still think the middle ground is the best approach, as you can't get by on high frequency sales with razor thin margins and expect much net success. I don't have any rock solid answers to this question, but wanted to post it for consideration.