FluffyKiller
Genre, time of day when posting, used tags, consistent time of update, the scope of the story, title and synopsis, cover, etc. A lot of factors would affect the rate of your collection increase. I'd suggest you try and check those things I mentioned above when doing a novel. Ask yourself the following questions;
Genre- Am I in the popular type of story? "Eastern Fantasy on WN? Heck yeah. Horror and Thriller? Meh."
Time of Day- Is my number increasing in sync with the demographic I have on the world graph?
Tags - Have I actually used the ability to put tags? "Oh sh*t, I didn't... that was why..."
Consistent Time- Am I posting at a constant pace?
The scope of the Story- Is my story actually worth reading? Highly likely? Less likely?
Title and Synopsis- If I were to read my title and synopsis, would I bother to check chapter 1?
Cover- "Seriously though, who clicks on novels with vanilla cover? Are you really that bored?"