Back in the days when the Advanced Roleplayer Section was being considering in the making, I've been part of the reviewing team that would read over people's posts and grade their writing style based off certain criterias. I wanted to share with you all those criterias so you would gain some sort of insight what people are looking for in "Advanced RPers". Use that rubric as knowledge to add to your own RPing database, or use it to review your own writing style, and improve it.
A fair word of warning beforehand. This rubric was made by me and thus is biased upon my own personal view of what a "skilled" RPer is. By no way does this mean it's the absolute truth, but I figured it might be a good reference point to start. Feel free to discuss about certain points you approve or not, as I believe guidelines can always be made better to further develop your RPing skills.
Without further delay, here's a link to an image of the rubric I made.