Let’s start with two SEO myth: meta keywords are death and should not be used.  Next, an heavy meta keywords optimized site is counterproductive for your ranking since the latest Google Penguin release. There are in fact rumors that also Bing used them to determine whether a site is a spam or a genuine site.

On the contrary, meta descriptions are crucial: they appear in the search results as the snippet description of the website/page.  Each page should have its unique meta description: search engine consider duplicate tattle tags or meta description as bad form and can actually penalize the page.

If you have a responsive website, duplicate content displayed on across devices is a serious issue.  Google recommend to add a canonical tags to all mobile optimized page, and an alternate tags to the respective web site pages. In this way, its search engine will easily determine and show the device-optimized page to the user client. You can also use canonical tags to discriminate yours  from a partner’s content.

In recent time, rich snippets that enables the site to embellish their search results with add-ons, such as customer’s ratings have gained popularity. Although it is still unclear how they might affect your website ranking on search engine, recent studies prove that a user is more likely to engage with sites that have richest snippets.

Last but not least, you can claim Google authorship by linking you site with your Google + account.