Putting all humility aside, I won every role contest I entered. Including some of the first ones when there were 100+ people on at peak times, only one winner was chosen and the prizes where HUGE.
I am also a published author and a paid copy writer, though I do not really do stories or fiction professionally.
And, I admit, my posts do not represent good writing in the least. (Verb tense continuity and dangling prepositions ftw.)
Here's what The Joker says:
The official guides to writing roles found on forums are an excellent resource to be followed to the letter. Zefarah's comprehensive RP guide is also a tremendous and well thought out piece. I actually got to be a mortal with Zefarah and...wow. She's someone to listen to. Any writer wishing to write well would be advised to read Roy Peter Clark's books. The better you can write, the better your role will be and while it does seem a bit silly to read whole books on writing just to write stupid CF roles, writing is a skill that will serve you well throughout your life and so I mention it here.
As far as length and detail go, role-writing follows the general rule of writing. If it's interesting, and if the words are necessary, there is no limit on length. For example, conventional wisdom dictates attention span on Facebook is short and so your Facebook ads should be as well. However, I have had tremendous success with very long form Facebook ads. Like, two pages in Word long. It works because the reader cares about what I'm writing, I'm writing well, and every word has meaning. When it comes to writing roles, tell your story completely in as few words as possible even knowing that may be one-hundred-thousand words. Or it may be one-hundred.
One very good tip...
Talk about your characters feelings and emotions. Emotion is how we interpret the world. We don't really remember the specifics of things that have happened to us, but we always remember how those things made us feel. Don't just address your character's physical journey, address their emotional one. The journey of an evil human seeking revenge is meh. The journey of a kind-hearted, sensitive human deeply wounded by tragedy who goes through stages of grief and anguish resulting in a callous, cold-hearted yet deeply conflicted evildoer is compelling and worthy of note to the judging immortal.
One not as good tip but still kinda good so I'll put it here...
If you know who will be reading the role and you know what they like you can tailor it to them. There was a time when a pregnant/new-mother Bitchnika was reading every role. I deliberately included a strong "a mother's love" element in all my roles because I knew it would tug on the heartstrings of my audience (Baer) and, lo and behold, I always got max role xp.
The best role I ever did was Icilio. There's a PBF. You can check it out.