What should I analyze?
Same page? - Do you and the search engine see the same page? There are some techniques that will make a search engine index and rank a different page. Here's how to spot this:
Look at the title - Is it the same as it appears in the results?
Why was the page ranked high? - If you can't figure out why a page ranks high, consider the possibility of it being a different page.
Use Google - Take advantage of Google's cache feature, which stores the page indexed by their spider. Look to see if it's the same as the page you see.
Is it a doorway page ? - Is it a page with few images that has a link? Does it look like it doesn't belong to the rest of the site? This may be a specially optimized doorway page, which focuses on the requirements for a specific engine and has a link to the site
HTML code - Analyze for all the elements you have learned about, including: HTML title, meta tags, ALT tags, keyword frequency and weight. See how many characters each one of the elements has, how keywords are placed in relationship to each other, etc