The first factor that can attract the attention of search engines is certainly the content of your website, search engines "hungry" of new content, yes "new" that's one of those magic words that can increase traffic to your site, and this is true for all kinds of categories, not just gambling. Try to give something new, try to get into the head of a new visitor and make him think: wow, that's really interesting .. or useful!
The second factor is the link exchange: do link exchange with intelligence, submit your site with relevant others in your category, please use the Google Toolbar and look for back-links of your competitors and believes that they are relevant links to Google, so is the kind of links that you must submit the PR is relevant, but not all, many pr0 can give you the relevant back-links, look for places that offer good content and not in their website many outgoing links.
The last factor is SEO, but it requires a bit of knowledge, try to read as possible about SEO, you must enter the forums, read articles and FAQs. SEO can really help you reach the top, be careful on page title, meta tags, body build, optimize the speed of your pages, go to Google Ad Words and look for the keyword search volume, related to your activity and start working with them , pay attention to keywords concentration, use bold text with sense, optimizing the H1 tag, use the W3C validator to fix the html code. Never give up, it's just the beginning.