Here are a few of many changes Google has made to it's algorithm. Paying attention to these changes can help you keep from wasting precious time when working on your search engine optimization.
Google is now more likely to use words from actual page content over words in a header or menu. Use your keywords often in the content of your website.
Google is beginning to depreciate values of anchor text (is the visible, clickable text in a hyperlink) within inbound links. Stop spending time coming up with variations of keywords in anchor text. Concentrate on calls to action.
Those searching for applications on google.com will begin to see more info about each app (reviews, ratings, offers, cost, date published, OS required, etc). If you are marketing an app make sure this info is listed and accurate.
Google has added "new signals" to tell you whether a page is original of not. They will not reveal what those signals are, but over time you will see less duplicate content in searches. Publish your own content.
Google will not show many search results from one website (or host crowding). This ensures a fair and balanced search result page.
Changes have been made to ensure that pages that only "partially" match the search are shown less.
Google improved it's handling of date-based search results and will feature fresh results in the organic search results. Bottom line... publish new content often.