Basically, Roleplaying (RPing) is basically writing a post or a piece of writing that adds to the plot of the Roleplaying story.
The most important part about RPing is your unique character, one which you will create for the RP. It must be a character that you are most comfortable and confident playing with. If you can find it easy playing a female or a mage or a bad guy, then go for it! But if you find it difficult trying to fit the limitations of your own character, then you will do badly in the RP story.
Secondly, RPing other characters is a tricky thing but if they give you enough information in their character's profile, then you'll be fine as long as you RP to their limitations. If you aren't happy with anything in someone else's post, then feel free to nudge them in the right direction by contact them or the gamemaster about it.
Thirdly, when posting in the RP thread, try to include some detail to make the sentence enjoyable and give the reader an idea of what you're imagining for that part of the story.
e.g.
Adrian walked into class and sat in his seat.
As you can see this sentence is quite dull and would put most readers to sleep.
Here's an expanded version:
e.g.
Adrian silently walked into the room, as gazes from everyone in the room watched him enter as if he had done something wrong. Quickly glancing around for his seat, he shuffled his way to it, ignoring the evil glances from his classmates. Sitting down, he quickly retrieved his stationary and remained quiet and motionless for the teacher to resume the lesson.
See how detailed the last paragraph was compared to the first where the last paragraph explained more about the same situation than the first paragraph did.
Fourthly, structure your post. It would be totally confusing if everything you type was in one big, massive paragraph so you split it into several mini-paragraphs to help the reader understand what you've written:
e.g.
He was just about to pick up the books when he saw a lone figure by the lake. Who's that? he wondered as he left the books in the arena and went towards the figure. He recognized the form to be that of Joel, and the boy appeared lost in thought and contemplating the water.
"How am I supposed to drag a body from underwater?" was relayed to Cru's mind and he recognized the young telepath's voice.
He wants to help his friend so badly that he doesn't even sense me here... So, the teacher reached out and touched the boy's shoulder, announcing his presence while moving his umbrella so that they were both shielded from the rain. "I think we'll need someone with a gift to retrieve the body for us. It's too dangerous at this time to go and get it by ourselves, and too dangerous for us to leave it for another day."
See how easily that is to read?
"" is used for speech between characters
italics is used for thoughts
and emboldened words are used to stress a particular word for emphasis.
Lastly, God Mode. This is forbidden to most RPers, except for the Gamemaster because he controls the RP. Godmodding is simply the controlling of another RPer's character that ultimately makes your character look better than theirs.
e.g.
Elesis came in and said to Charles: "Liya's gone, your highness, and Akil too."
Menos felt strange as Elesis walked in, something that seemed...off with the female warrior. Just then she witnessed Elesis pull a knife from behind, drawing it from it's sheath which was equiped to her belt. Acting upon her instincts she gathered tendrils of flora and unleashed them upon Elesis.
"Your Highness--Get outta here! Don't argue, don't wait--Just GO!", Menos cried at Charles while she strangled Elesis with her magical vines but her actions had no effort as the young warrior ripped the slivering constraints apart and with such speed and strength, Elesis sprinted and knocked Menos into a nearby wall. Elesis pulled out her knife and stabbed Menos in the stomach.
"That wasn't very nice.", Elesis said with a growing smile.
See how Elesis defeated Menos, making her look better than Menos? This is forbidden in RP, unless agreed between RPers, and if the Gamemaster does anot approve with what you've posted because of godmodding, then you will edit your post accordingly.
That about ties everything up I guess.
If you have any queries or questions about anything I've written or forgotten about, please feel free to contact me.
Happy Roleplaying! :D