There are 12 steps of onpage seo that I always abide by when writing my blog posts. I focus on quality, relevance and select my keyword carefully. Then I use the keyword plugin so I get all of the on-page seo correct before publishing the blog.
This is step 1 of my 3 strategies I use to rank very high in the search results on the major search engines.
On page SEO is the 1st step in the overall strategy and a very important one. Make sure you do it right!
Using the keyword tool plugin ensures that it is done correctly.