First note that any page in your Web site can be reached through search so every page needs Landing Page Optimization.
Snippets
Its not just about getting a high page rank and SEO as you must communicate value at the outset (Landing Page Optimization) and this includes the Search Result Snippets. Snippets can be linked to landing page optimization as once you get visitors to your site, you must keep them. Exacerbating this complexity is that visitors can arrive anywhere in your Website. This leads us back to the Abstract Site Design tenets as we must have a consistent grid based layout (CSS) with clear information supporting navigation by recognition.
Here is an entire Google Webmaster tutorial on Rich Snippets. If you are a Web Designer click the YouTube icon in the lower righthand corner as this will take you to YouTube so you can watch the entire series. Note it would be beneficial to follow the Google Webmasters on YouTube as well.