There are various techniques and strategies used for SEO, and these often change as search engines continue to adjust their algorithms. Here are some of the most common techniques for SEO:

1. Keyword research: This involves researching the keywords and search terms that users use to search for information. This helps to optimize content and identify opportunities to rank for specific keywords.

2. On-page optimization: This involves optimizing the content, metadata, images, and internal links of a website to make it relevant and useful for users and search engines.

3. Technical optimization: This involves optimizing technical aspects of a website such as load speed, mobile responsiveness, crawlability, and indexability.

4. Link building: This involves acquiring links from other websites to increase authority and relevance. However, this should be done in an organic and ethical manner to minimize the risk of search engine penalties.

5. Local SEO: This involves optimizing the content and technical aspects of a website to be more visible for local search queries, such as adding local keywords, listings in business directories, and obtaining positive customer reviews.

6. Content marketing: This involves creating valuable and relevant content to increase user engagement and drive traffic to a website.

7. Social media: This involves using social media platforms to increase the visibility of a website, engage users, and acquire links to the website.

It's important to note that some of these techniques may not be suitable for every website or industry and that search engine guidelines and policies should always be considered to minimize the risk of penalties.