General guidelines for the RPer. Generally RPing is an art, there must, of course, be a charachter. You can do like I did and introduce a charachter that is nothing more than a name and a pic and have others build a story as you go, or you can make one up on your own. There are several threads around here that can help with that. But that's only the beginning, you must also have an RP style, many rules posted on the first page of a thread give some general guide lines. Most RP's are semi literate meaning the posts look something like this:
Semi-Lit
That one guy walks into the bar and sits at a table. "I need a drink."
Short sweet and to the point. Others are Literate, like so:
Lit
John, seeing a quaint little bar decides to investigate, though he needed a drink any way. As he walks in his boots make a dull thunk against the wood floor. Making his way through the bustling seating area he sits at the bar and places his order with the bar keep. "I'll have a scotch on the rocks."
Notice the detail, I kept it short just to save time but you get the idea. Then there's the Illiterate.
Illiterate
*walks into bar and sits* Nice place... *grabs drink and sips it*
You get the idea, basically bread and butter, while the others are Full Meals. The true master of the RP can write pages without even trying. Sadly I'm not there yet.
The most important thing though is to have fun!