The length of his posts have nothing to do with the quality of it. You can post a single sentence and still be on topic and still be constructive. There are people here posting long lines just to make it look like constructive, it's not.

OP has no control over his rank. The only thing he can do is be active (which he isn't anymore as I write this post) and wait for the time until his activity count is sufficient enough to get a decent income from signature campaigns.