Post Length

2. A literate's stance is determined by their use of grammar, word choice, and character depth more than the length of their posts.

The length is a side-effect.

No, I'm serious.

Too many people think that, to be a good roleplay, you must have long posts. That's all. Just long posts.

But it's so much more than that!

Your grammar has to be at least decent, obviously. NOT PERFECT! I cannot stress this enough! My grammar is NOT perfect. I use run-ons. I use fragments. I mix things up, invert things if I feel like it. It makes my writing more interesting, adds flavor to the character, depending on the character I play. Perfect grammar is boring to read. On the other hand, chat speak and NO grammar is simply atrocious. Find your happy medium and cling to it.

I'm going to play English teach here.
'She was happy.'
'He had brown fur.'
It. Doesn't. Work.

'Joy filled her, making her eyes sparkle and a smile spread over her face.'
'His pelt was hued of chocolate, flecked in places with chestnut and mahogany.'
THAT'S more like it!

See, certain words have certain connotations - that is, they make you think of different things.
Whelp.
Pup.
What did you get when I said 'whelp,' ey? It sounds negative, like an insult. Whereas, with 'pup', the feelings are positive and energetic. It can take hours, literally, to find the perfect word, and sometimes your word doesn't exist. You have to use a phrase, instead. But the subtle difference it makes has dramatic effects overall.

Go with the connotations first. Connotations to denotations, your writing will improve dramatically.

And the post length?
FORGET THE POST LENGTH!
Two sentences written with the right grammar, and the right words, for your character will have infinitely more effect than five bland paragraphs.