Who are you targeting? If you are advertising to 'everybody' that needs hosting, good chances you won't get a bite. You you need to find your target audience and market towards what they need!

If you have never done marketing before, I suggest you look up some articles or even buy a bookd (or borrow one from library) about marketing and promotion. Just to get a general idea of what it is all about.

Ideas for really affordable and free marketing for your hosting business... post in forums , post in forums advertising areas, write articles about your topic and submit them to popular article websites, start a blog!, get listed in search engines (free if you go around and submit them yourself), offer free hosting if webmasters will recommend you on their website, post in classified ads (craigslist), and get creative - do something that hasn't been done before!