Let me ask about the number of posts in your blog. Do you have several or already have a lot of them? It is true that more blog posts also means greater chance of being displayed at the search engine pages. Your ranking in the search engines would be greatly affected by the number of times you mentioned the "keywords" in your content.
For instance, in this blog, my Google search engine place as of today, August 19, 2008, for my blog post entitled EMAIL SCAM # 4- GAMBLING APPROACH*, is number 10, although I didn't make it "yet" to the first place, at least in about two months time, I made it to the top 10.
Some might be wondering how I did it. Honestly, I did not spend a single dime to be displayed in top 10. But, I will admit that I spent a considerable amount of time and effort for it.
Let me share to you my secrets bit by bit. While it is important to mention the relevant "keywords" several times in your content, it also makes sense for you to incorporate the appropriate keywords in your meta tag, because many search engines directly refer to the meta tag for indexing.
I suggest that you visit the free meta tag analyzer under the free tools tab of submitexpress.com for you to have a free analysis of your blog's meta tag. Based on the analysis, you can correct the detected errors by your self.