Basically, there are two types of SEO :
On-page SEO - On-page optimization refers to all measures that can be taken directly from the website in order to improve its position in the search rankings. Blog Post Title, Submission of XML Sitemap, Post Permalink Structure, Implementation of Google Analytics, Heading Tags, Keyword Density, Anchor Text Optimization, Meta Tags, Alt Tag Optimization, Addition of Images, Content Interlinking, Title Tag Optimization, Web page Specific Meta Tag, Linking out to External Websites, Write Engaging Content, Keyword Research and Evaluation.
Off-page SEO - Off-page optimization is an important & effective part of SEO. Off-page SEO techniques are very useful for improving website ranking & generating quick traffic towards your site.
Few off-page SEO techniques are-
Social bookmarking.
Forum posting.
QnA.
Article submission.
Video creation & submission.
Web 2.0.
Microblogging.
Press release.
Info-graphics creation & submission.
Blog posting.