Just in case you have not read part one, here is a link to it: SEO – what is it? Pt.1
Some SEO specialists may argue that paid results are not the best way to get visitors to your site, this could be because some people actively avoid the sponsored links as they feel that paid links are not necessarily going to be as relevant to their search query as organic non-paid results might be. Another reason why people may argue against the use of paid results is that the results are not always the same, this is because search engines rotate between a list of website links which pay to be the sponsored links on their site which means your website may not appear at all for a search term you wish to appear as a result for.
However, it’s probably a good idea to have some paid for sponsored results or advertisements even if it is only as a trial to see how effective they are at driving traffic to your website. Whether or not that traffic will give you more custom can only be determined through advertisement experimentation.
Specific words can be cleverly used on your site to get the algorithms search engines use to place you in different search term results or to place you higher in results for search term results in which you may already appear. Optimisation can targeted at different types of searches, this includes image search, video search and news search. SEO does not just involve changing the content you actually see on a website, other content such as meta data and html code may be changed to give more information about your site to the algorithms that will scan your site content. SEO can also involve the creation of sitemaps, adding alternative descriptions to images, introduction of backlinks and in some cases where the current website is not being properly analysed by search engine algorithms website restructuring.
Obviously this is not all there is to know about SEO, but this should explain it in its most basic form.