Everything people have said already is good. But there are also some other factors: the content you write and what you write are critically important. There is a hubber (check her out on the hubpages homepage on success stories) who has written 96 hubs and makes at least $650/month. But, she has written what a lot of people want to read. Others have written hundreds of quality hubs and somewhere between 500-700 hubs is where the money gets to be between $1000/month or more. None of these hubbers are new, though. The people who make the most have been around for 2 years or longer and they write consistently.
I'll say one thing though: in my three and a half months here, I'm already making money and expect my first check within the next month. I focus on writing every day or every other day. I try to write high-quality hubs that look good, have no grammar errors (I hope), good keywords, and use at least 6 of the capsules (eBay, amazon, text, pictures, polls or quizzes, tables or maps). I also find that the hubs where I take my own pictures or use my own drawings are the ones that tend to do the best. Really, you DO want to write something that other people in HP will comment on, but ultimately you want traffic from the search engines to sustain you over time. So, while it's really good to write what other hubbers will want to read (like an HP tutorial), you want the rest of the world to read what you write. So, you have to really focus on search-friendly, evergreen stuff to really pull in the traffic. You have to remember that it takes about a year for hubs to mature, and about three years to really work their way around the web and deep into search-engine algorithms. So, with the hubs I've written, they haven't matured nor are they that searchable, yet.
But, you CAN make money before that happens. It's not easy, and you will put in hundreds of hours before your efforts really seem like they're worth it, but once you start going somewhere, you REALLY will. Hope that helps. You've been so thoughtful to comment on my hubs; I thought I'd stop by and repay a little HubLove. :)