some of the suggestions especially for Google: 1. Use rich snippets which shows a video or a product review in the search result. 2. Categorize your sitemaps according to your product group. 3. Optimize for image search. And of course follow other general stuffs like optimizing page titles, meta desc, etc.
Make meta tags for every page as per relevancy. Always keep in mind about meta tags length(Don't exceed the length size). Use proper H1 tags. Target long tail keywords, it will help you to rank fast on search engine and best part of long tail keywords are it drive most of targeted traffic to the site. Make a blog on your domain and update 2-3 times in a week, this will make your site updated regularly.
Social media becomes more important, having constant activity on Facebook, Google+ and other networks can give good "brand signals". Focus on quality of content (product reviews), Google Panda updates seems to devalue low quality pages.