The goblins have always known that by shouting out their wares and services increases the number of trades they will complete in a day. Walk down any goblin controlled town and you’ll hear their shouts or ‘barks’ : ‘Have I got a deal for you!’
So, what works for the goblins will also work for you. Learning to use Trade Chat in the Auction House will greatly improve you sales. Read this article on How to Use Trade Chat in World of Warcraft.