Due to large dynamic pages and the ability to develop some of the autometic functionality dynamically, large shopping cart or other ecommerce website can take advantage of this. Below are some tips which is more important to develop for ecommerce website which sells product in bunch.
Canonicalization: Most of the ecommerce websites have large no. of products and its filter criteria to filter according to the type of products. For example for general laptop category page, there might be filter criteria as per its brands, processor speed, memory of the ram etc. According to these filter parameter, new pages being generated to display products as per user selection and these pages can get conflicted and considered as duplicate with original pages you have developed for promotion. You must define canonical URL to all these filtered pages.
Automatic Title Tag Creation: I have observed in many websites products pages without proper title tag. Due to large no. of products we have to retrieve the value of from database and have to set it in its title tag dynamically. With current technology it is easier to specify dynamic Meta tags from database.
Inter linking : iF you want to take advantage of the size of your website, efficient internal linking between pages is necessary where you can use your sense and can define criteria for inter linking between pages with help of developer.
Url Structure: You must accurately analyze the URL structure of your product pages and main category pages. If the product pages are not being cached and indexed easily, you must adopt the url redirection or re writing and the same way for main category pages.
Above are some tips which suit specially for ecommerce website. There are other tips as well like content optimization and basic on page changes which I am not specifying here.