SERPs pages consist of paid and organic search results. SEO focusses on improving the ranking of the organic search results. However, where a Google Adword campaign is running it will also benefit from SEO efforts. This is because the Google Quality Score is used to determine both the ranking and cost per click for paid advertising. The more relevant the page the higher the Google quality score.
Typical page will have 10-organic results that will link out to different web pages.
They will all have a title, description and URL. It's important that these components are optimised.
The search results are continuing to evolve. Today they consist of more than just text and web pages. They show blended results of web pages, images, vidoes, local serch, maps, news, products and instant answers. The thing to remember is that there are lots of opportunities to appear on the serach results pages.