There are many factors that Google uses when determining which pages to crawl and index. If you address these two important factors, it should help:
1. Check whether it is easy to crawl your pages by disabling JavaScript and noting your crawl errors in Webmaster Tools.
2. Boost the quality of your site's content; it should be unique and compelling.
Note to do the above you must have Google Webmaster Tools installed on your website. It is an important tool that everyone should use. More recenlty, Google has even started providing this information within Google Analytics itself.
