On-Page SEO means more now than ever since the new Google update: Panda. No longer are backlinks and simply pinging or sending out an RSS feed the key to getting Google PageRank or Alexa Rankings, you now need on-Page SEO.
So what is good On-Page SEO?
First your keyword must appear in the title. Then it must appear in the URL. You have to optimize your keyword and make sure that it has a nice keyword density of 3-5% in your article with relevant LSI (Latent Semantic Indexing). Then you should spread all H1, H2, H3 tags in your article. Your Keyword should appear in your first paragraph and in the last sentence of the page. You should have relevant usage of bold and italics of your keyword. There should be one internal link to a page on your blog and you should have one image with an alt tag that has your keyword…
A good On-page SEO for WordPress would be WordPress SEO by Yoast. Give it a try!