The on-page optimization for shopping cart site should be done the same way as normal page, but there are other important factors in shopping cart sites which many SEOs or webmasters overlook and fail to execute and i’m going to explain the same.
First of all i’ll admit on-page optimization of shopping cart site is daunting task and the person who handles it should have patience and take step-by-step approach
Shopping cart sites includes many page for product/category. So product/category keyword optimization is first along with the description of product/category with keywords. Don’t forget to add catchy words in those descriptions to attract users/customers. I personally use catchy images to attract humans eye.
URLs of the product/category page should be optimized for those keywords. If you can create a review page for product/category that would attract lot of customers.
Cross link related items/products/categories if it fall under same niche. Don’t forget to check broken links/internal links (very important) test your page before it’s live.
And the most important for every e-commerce site is page speed/load time.
Optimize your image, use external stylesheet or javacript files
Only when someone add something to the cart use SSIDs
Only when someone checkout a page or enter confidential information use SSL
Use of cache and stored procedures is a must for database in ecommerce sites
Effective validation of all fields with clear guidance for users is a must (Very very important point)
Rest all the normal on-page SEO. I’m exhausted, should take a break for compiling a long note in short summary. I hope this helps you. Good Luck.