There are two types of techniques in SEO.one is black hat SEO and one is white hat SEO.In black hat SEO it is not necessary to have original content but in white hat SEO it is must to have original and unique content, duplicate of content is not allowed here.

Black Hat SEO technique
White Hat SEO technique
Gray Hat SEO technique

how many SEO techniques do you know?
 

There are many SEO techniques that play an important role in optimizing your website. I am well aware with the SEO techniques, but some of the techniques that I usually prefer are Off Page techniques and they are:

Article submission
Guest Post
Blogging
Forum Commenting
Blog Commenting
Infographs, etc

There are other On Page factors as well that I have worked upon as it is important to follow both the aspects of Search engine optimization.

References http://www.dpfoc.com/canada/seo-services-calgary.php

Mostly all. But use following ones as per as Google updates-
- Blog Commenting.
- Blog posting.
- Article Submission.
- Infographics
- Social Media Marketing.
- Social Bookmarking (Only High PR sites).

all off page and on page techniques.