Okay, so I'm pretty new at youtube, but I can't imagine the viewers have wants much different from other sorts of internet media, so I'm going to throw my two cents in:
Make sure viewers know your upload schedule so they're not always guessing when the next one is.
Stay social with viewers and other youtubers.
Do a little research on SEO and Keywords, because it never hurts.
And always remember that it takes time to build a reputation and to get the views you want, you just have to stick with it.
I don't really know you or what you're already doing so I can't offer to many suggestions, but do I hope you get your stats back up soon!