This depends usually on a combination of how frequently/regularly you update and how well you stay on the popular/trending/fresh lists, as well as being active elsewhere (like the forums). Unless you're premium, you're only option is staff picks. Which means you have to be visible enough, pop up often enough, for them to notice you. Then of course you need to have a good story and at least decently clean writing. I don't know if number of episodes matter (like, will they feature you if you only have a few episodes posted?)
I was lucky to have been featured after a few months, but I can't really tell you why. I update frequently and regularly, and while I'm never really at the top, you can sometimes find me somewhere down the popular list (sometimes quite a few scrolls down ). Not active recently, but I do also hang around the forums. No idea if that matters, though.