I have opened a blog on WP since June, 15, but my blog has only been indexed for 10 pages. I don't know what goes wrong with my blog. Please give me some suggestion. This is my blog: http://susanjia.wordpress.com/ Tahnk you!
Give it some time. Google will crawl all your pages. Give links to the uncrawled pages in your post, and build deeplinks to them if possible. I would have advised you to submit a sitemap, but I don't think you can build one with a wordpress.com blog.
With your site being at wordpress.com, you can not really do anything about it from there. What I suggest you do is submit the RSS feed from your site to RSS feed directories. Create a Yahoo Blog Log account and setup your RSS feed in there. That way your recent blog post will show up on several websites where google can find a link to them. Here on digital point there is a recent blog post feature. Enter the address to your RSS feed into your profile. That will point google towards your site also.