This is pretty simple guide for being a trustable lw, alchemist or blacksmith.
With being trustable, I mean that your customer can trust you and recommend you to other people.
-Use good english with macros. Nobody wont trust you when you say "i can maek u this item gief mats and fee"
-Always link the profession.
-It helps being in a well-known guild.
-Don't spam with macros. People hate it. :P
You can also add to the macro that you have extra scam security for the customer.
How do we do this? Let me tell ya!
When the customer asks you, what is this extra scam security, tell them that you will give them a letter, which they can then give to Blizzard if you scam the customer.
When you know the item the customer wants, log to your alt, send letter with item's name, your name and customer's name.
For example :
Extra scam security for [Trollpown] (the customer) by [Taurenpown] (You) for item [Some random flask] (the item).
Then give copy of the letter to the customer, and tell them to keep it, and send to Blizzard if you scam them. Tell them that you will be banned if you do so, and with the letter the customer has proof of the scam. Also tell them to take screenshot of the item transcation, and to send it to Blizzard support if you scam them.
This will make you alot more trustable for customers. And will propably get you new ones too!
Enjoy!