I have worked on many e-commerce sites. And find out many thing which face once we start workon E-Commerce site
1) Broken link issues
2) Duplicate/canonical page issue
3) Delete the seasonal pages
4) Product accessing issues
5) Complex e-Commerce solutions
So what needs to done for this?
1) Fix the broken links as much pages you can
2) Put the customized 404 page
3) Bread crumb don’t miss it
4) Don’t make users think do the job for them.
5) Branding strengthening
6) Testing all Truths – for all the landing page
7) Put Secondary Conversions see below
8) Canonical issue must be removed use URL paginations http://support.google.com/webmasters/bin/answer.py?hl=en&answer;=1663744
9) Images must be small sized and have put “alt” attribute in a descriptive way
10) Good headlines and test as much pages as we can
11) Put the appealing page title on you web page. It should take some words in our page title like e Buy now, call now, free, offers, hurry etc.
12) Put the small summary beneath your products if possible then put some testimonials also.
13) Auto expire pages should be on the site, if we provide limited period offer for a product based site.
14) Make a contact form which is easy to fill and should not have un-necessary fields like - how you find us. etc.
Don’t call submit button – change it like
I.Start your order
III.Captcha Irritates user, they stop conversions. (we have use hidden code which will be stopping unauthorized emails.
I hope that will help also once you do SEO for e-Commerce portal.