1. Your site is too young. It takes 2-4 weeks to index the site by Google. Yahoo and Bing (Microsoft search) are faster. I encourage to add your site at least to Webmaster Tools and describe sitemap, it makes easier to understand the site by Google robots. Additionally you may add the site to Yahoo Site Explorer and Bing Webmaster Center. These tools allow to see problems on the site and get optimum indexation.
2. One common mistake is that "robots.txt" file (in the website root directory) disallows robots to crawl the site. It's usual, that during the site development webmaster disallows access by robots not to index site in the middle of progress. I've seen cases when "disallow" flag is mistakenly forgotten in robots.txt file and site is not indexable at all.
3. Blog or WordPress engine? Check if your site is checked as publicly viewable, viewed by search engines, etc. It's in dasboard / privacy section in WordPress, just one example.
4. Your site is baned by Google. Links to the sites with bad reputation, link farm, link trading etc? One common reason is that website developers try to hide links of their own interest into your site. When Google finds hidden links, it bans whole domain. Register your website in Webmaster Tools and it tells You right away, is the site banned or not.
5. Other techniques used on the site, not allowed by Google? Read Google webmaster guidelines and bear in mind, thet Google is always one step ahead. There is no fooling in order to get extra link juice etc.
And remember, not indexed by Google = not existing at all