SEO is must part of any blog, who is ambitious to be on top of the Google, Although there are too many factors which are responsible for getting your blog on top of the Google results, but SEO is among the very basic and very effective. SEO is a ever changing process, you need to change your strategies, your goals with every new SEO updates.
But basic techniques somehow remain same. Like, Good titles, Good keywords, Nice descriptions, Keyword Density etc. Every small point I wrote is a sea in itself. You can write a full book on any of above said word.