Here are some tips on decent rp...
know your character:
take some time to think about the background of your character. Where were you born? Why are you a certain class? Where do you live now?
* Not all characters have to have a tragic past, your parents can be alive
* You're not the son of Sargeras, don't go there
* Read up on the lore, you don't have to know all, but when you're a dwarf you should at least know who your king is :p
When you do meet a stranger don't go telling him your life story, IRL when you just lost a dear friend you won't go telling a perfect stranger that.
Instead, ask them what they are doing here, where they are going, if they want to join you for a pint. Some nice rp just begins when you're both waiting for the boat to arrive.
I can not stress this enough No and I mean NO ((bracet talk)) in /s it ruines everybodies rp experience
use /w to give extra clues or talk ooc... When a lot of you are rping together form a group and use /p to give guidelines
Try to get an rp outfit together. Some clothes you wear when not questing. You won't look like you were dressed in the dark and it's an open invitation to others to start some rp with you.
Walk instead of run... Best way to show you're open for a nice conversation.
Install flagRSP2 nice little roleplaying addon that let's other know you want to rp.
you can fill in a surname and a little physical description of yourself (colour of eyes, expression, scars, etc)
For the rest, when you're new let people know, they will gladly help you and forgive your mistakes. A lot comes from experience and the only way to get that experience is to try...
One last note on Goldshire, sin city of Azeroth...
For some the worst place to find decent rp... sometimes it is, sometimes it isn't.
When you do go there just keep away from the duals, sons of Illidan and Sargeras or vampires. The true RPer will recognise you and some nice rp can be born