Each SEO provider follows their signature tactics to improve their users web presence. In general they register the website and sitemap.xml with various search engines,submit the website to directories,include popular keywords, topics, Robots.txt file and Robots Meta tag analyzer,etc.You can choose a SEO provider based on user reviews that bring in more information about the respective provider in terms of reliability,reputation,support etc. I suggest you to use the SEV(Search Engine Visibility) from
http://www.tucktail.com/search-engine/seo-services2.aspx?prog_id=447401&pl_id=447401 which covers the major SEO techniques and helps in obtaining the desired web presence.