I have no suggestion on how to make more gold right now but I think that no mather what it's very important to sell all blue or epic stuff before Cataclysm is out : value of epic gems or epic crafts is only going to decrease now until the point nobody wants them anymore. Who will want a Wolt epic gem when a Cataclysm gem will give more stats ?

On the other hand, I'm pretty sure (currently) common reagents like uncut green or blue gems will see their value increase a lot in a few months when people will be willing to powerlevel professions to the new cap according to the new lvl 85 benefits. So I've stopped selling them now the price is so low and I have started to stockpile them until the day people will pay a fortune just to get their rerolls ready without having to farm all the mats :P So I don't know who to make more money now but hope to be planning well for within a few months.