How can write the SEO complete blog ?

Seo is both On-page and Off-page type. You need to address both for your blog.
If you are mentioning about the content in your blog, then you need to select the correct keyword, use it optimized number of times, meta description, title, permalink, add relevant links, image optimizing, paragraphing are some of the ways you can do it on the content.

You need to optimized your SEO blog with keywords and relevant information. 

You need to give as much information as you can and also add your targeted keywords but don't do keywords stuffing its harmful for your content

you need much information about Search Engine Optimization, Keywords, Search Engine Updates