SEO is a glorified name for developing good and visitor friendly websites.
In fact, Google, by changing/upgrading its algorithm frequently is perfecting the art of bringing in better and closer search results, and making it difficult for others to catch up with it.
Instead of
SEO, the better word to describe a professional/activity which promotes a website is a marketer or website marketing.
SEO is a part of website marketing. In fact, for one of the sites I promote, only 50 % of the traffic comes from search engines.
There are hundreds of techniques to get traffic but no one will reveal them. It is much more profitable to go work on optimization.