Search Engine Optimization (SEO) is a technique that helps search engines (like Google, Bing) to find your website page & rank them higher in the niche of millions of other sites in response to a search query. In simpler words, it enables squeezing traffic from search engines to your website.

Below article provides high level insight of Search Engine Optimization techniques:

Search Engine Optimization by Sachin Dhir on Scribd

Enjoy!!