Runeology

Roleplaying, or the way it's usually done here anyway, is quite simple.
Someone makes a thread. The first few posts contain the introduction (has to grab the audience's attention), the rules, the setting, the beginning of a story and the thread-maker's character.

To join, you post your character and ask nicely But don't spam or flame if they refuse, listen to their advice and maybe make a few changes to your bio and ask politely again. Do not get upset if somebody says no to letting you join, there are lots of good RP’s out there and you may need a little experience.
If they say you can join, they your character can enter the story. He/she is controlled by you and you only; you can't control someone else's either. Gradually the thread maker and the players progress through the story to the end.
You must make sure your posts are descriptive, use proper grammar and that your character does things that apply to what he's like.
For example, if your character is always happy then he/she wouldn't say 'go away or I'll cut your head off.' Similarly, if your character's personality is evil and shady, he wouldn't jump into a room holding a balloon and shout 'does anyone want a free balloon? I'm just in a nice mood today. How about a group hug?'

#1 Moderation is the key:
Having an uber-powerful character that can, with one withering look, decimate everything, does not get you any friends. It is unfair and annoying to those who wish to play properly; it also ruins the game for everyone else. Having a well-balanced character is what people want.

#2 Grammar is as important as Granddad.
Typing without basic punctuation, grammar or spelling it can be very difficult to decipher exactly what is being said. If you're not sure of the spelling, type it out in a word-processing program with a spell checker so you don't have to worry or get out the dictionary.

#3 Leet must die
Avoid the use of leet or other internet speak which includes the use of y, u etc. Use full sentences and proper sentence structure. Colloquial accents are fine so long as you stick to them and they are easy to understand. "Arr that it be" in one post then "yea course it is" would be a little out of character, so if you wish to use silly accents then for continuity you need to stick with them really. Also avoid the use of asterisk to signify actions. Use full sentences to display your actions instead.

#4 Use the door not the wall to enter a roleplay.
Time your entrance as best you can. It is no good those already playing being engaged in a fearful battle for their lives when along you come and start chatting to them. It is best to enter while they’re walking along a road or the like.

#5 What’s in a name?
Remember to include your name often instead of he or I as it can be difficult for latecomers to know who you are without referring constantly back to the character bios.
An example of this would be:
“Anlath entered the room, his dark cloak flowing behind him as he walked. The secret chamber was dark, and with a few words Anlath conjured a magical light to aid him”

#6 A break from the norm.
You dont always have to be the generic elf, dwarf or human. Branch out, be wacky (within reason) create your own races (but be sure to say what they are!). As long as the cap fits wear it.

#7 SPAM
Don’t spam, that includes making lots of single line posts rather than editing your original post.

#8 Godmodding
Godmodding is where you control other characters without their permission. This is frowned upon for obvious reasons as it is annoying and unsporting. People favor those who dont touch this with a ten-foot barge pole.

#9 Autohitting
Continuously attacking another character without giving them a chance to defend themselves. This again is unsporting and more than a little annoying. Avoid like the plague

#10 Be interesting in your bio.
Just like in real-life with a resume; short, vague and not very detailed (much like a dwarf really) is not the way to go. A two-line bio makes for a very boring read. Be creative and interesting, delve deep into your imagination and create something worthwhile to read (though don’t be too long)

OOC:
------
Use this term sparingly. It means for you talk out of
character, which is normally frowned upon in an RP. If an
RP’er overuses this term they might find themselves being
asked to leave the thread or RP. Too much OOC is
considered Spam!

Saving space:
------------------
If you seem to post a 1 liner (1 lined post) and then you come up with something to add, use the edit button. Don't continuously post more 1 liners. Combine them!
Also if you post OOC before you have a bio in edit the OOC to
replace it with your bio! It saves space etc.

SPAM:
---------
If you post too many OOC's after each other it is considered SPAM.
Posting a pointless message before you even post a bio such as:

I like tacos.

After creating a bio AND being accepted into a role-play, you are expected to create an introductory post. This may seem obvious to most of you, but let me inform you, getting posts like "Ok, great. Um.. How do I start?" is extremely irritating.

Firstly, make sure you use proper English. I cannot stress that enough. USING ASTERISKS AS ACTIONS = BAD. Terrible posts are no longer seldom-seen and many of them look like such:

" *walks into city and sees person* hello who are you "

Perhaps it would be easier to grasp if I created the same scenario but with proper role-play grammar.

"Timothy strides into the hustle and bustle of the town, grasping his sword lightly. Looking brightly around, he eyes a stunningly beautiful young lady looking distressed. He proudly walks over to her and exclaims, "Why hello there, my lady. The name is Sir Timothy, Knight of Falador. How may I be of assistance to you?"

As you can see, the second post would be greatly more appreciated than the first.