Youtube or Google it. Can't hear that stupid question here anymore. If there is THE WAY to farm gold, telling you and others would mean it is very soon not useful anymore. So check your server what sells good and farm it. That means thinking and reading from you
Sorry, stupid question i guess, but, how do i know what sells good on my server? U mean looking on AH ?
Amongst other things, pay attention to the trade chat to see what people are selling. There are plenty of guides on how to make money out there, figuring out how to automate it is the next step.