These are not guidelines.
CREATING A ROLEPLAY
Title
It's basic, but necessary. It gives the roleplayer a vague idea of what your roleplay may be about, and attracts interest. Other information you may want to include in the name topic of your roleplay is its status: Is it accepting or closed to applicants?
Introduction
Be it IC or OOC, give people a starting point for their posts. Colour in the setting so everyone knows what's happening around them so they can interact.
Backstory
Give a little rhyme and reason to your roleplay. Why is your character where s/he is now? What large-scale past events are drawing your band of roleplayers together? What happened in the past that would majorly effect the present situation of your roleplay?
Character list
You don't need profiles, per se, but at least quick reference post to let anyone who's interested know who's playing who.
Information
Give information about your roleplay that you think is important. Maybe go a bit deeper into the backstory, expand on world knowledge, or put other general need-to-know's somewhere in the roleplay. The setting and timeframe of the roleplay, the landscape, the species, cultures, religions, technologies, magics, or anything else you deem important.
Expectations
Let everyone know in the beginning what you're expecting from them. Specific requirements for posting, rules for joining, things of that nature.
Updates
OOC or IC information, you may want to have a post dedicated for updates. Maybe a recap of the roleplay so far, news that certain roleplayers are going to be gone for a while, or maybe important plot twists that need noting.
KEEPING IT ALIVE
Most of you have never been in a roleplay that has finished. Why do you think that is? Poor planning on the GMs part? The roleplayers who joined? Life butting in? Whatever the reason, nine out of ten roleplays never see it to the end, and it's everybodys fault.
YOUR CHARACTER
Creation
Think about what you're doing here; it's important. It's the most important part of joining a roleplay. Not creating a profile, but creating a character. This person will be your conduit to another world. It's not as easy as plucking a name and giving it a pretty face. You have to breathe life into the character to make it believable. You can't have robots in a medieval fantasy. You can't have magic in a realistic setting. Your characters appearance, personality, beliefs, actions, way of life- everything has to fit into the society of the roleplay, or you throw things off.
Appearance
The girls want to have killer curves with long, flowing hair. The boys want to be tall, dark, handsome, and strong. Mysterious, a curiosity, a cliche. Try to expand your horizon and create a character uglier than sin. A character that's truly a physical outcast, not just some emo/punk/goth kiddy who's going through their teen angst phase. I'm not talking a scar here or there, I'm talking major deformities. Maybe pimples. Have a chunky character that jiggles when he walks. Not everyone is beautiful.
Personality
Attitude
History
Abilities
Following through
AESTHETICS
Paragraphs
Speaking
Thoughts
Details
I don't believe in long posts for the sake of long posts. It's nice to develop your character and open up his or her history, but there's no reason to drop it out there just to fill up space. There's no reason to daydream your character along, describing every butterfly that flutters on by. You want your post to be on point with the roleplay, not flung out there in the middle of nowhere. Not only is it hard to respond to, it usually has little to do with the story.
Ellipses
They make you look some kind of stupid when overused, so stay away from the dreaded three dots. And definitely don't add more than three unless it's the end of the sentence.
Fonts
Small size + bright colours = wtf. You want people to easily be able to read through your post, so be courtious when submitting your piece.
Editing
We all love that good faith effort to keep a post simple and clean. We want people to be interested in our peice of the roleplay, to read through and respond to it. That can only be done if your post can be read. It only takes a moment to skim through to try and catch the more obvious errors, but it's always lovely if you take more than a moment to edit, trying to make your post the best it can be.
EMOTIONS
While conveying ideas in fiction, you can't properly connect without emotion. Our daily lives are filled with a spectrum of emotion so vast, that it could cause you to explode if experienced all in one moment. Expressing your characters emotion isn't as easy as it sounds; dialogue alone isn't enough. You have to show it by using their words, their thoughts, and their actions. Cliche lines such as "green with envy' or 'black rage' aren't enough and do very little for the reader. A truth and clarity as well as something realistic have to be present.