This is method that I have used in the past and have too won the first page. The professionals in the post are correct in saying go for a more competitive keyword. The beautiful thing about blogging is that if you find a blog that is 1) relelvent to your site 2) your keyword 3) has good PR and SR with an engine it's good but harder with more competitive keywords. Google can only fit so many entries on the first page. So here is what I say, if you stick with SEO and follow and test test test test you will one day if you are lucky get on the first page for a competitive keyword. It does all depend on how many seo companies leave and breath SEO.
Its highly depedent on keywords you are working very popular keywords take long time to rank 1st in Google. Using unusual keywords can help in getting high easily.