Answering a question on Wickedfire here.

If you own an Ecommerce site and don’t know where to begin on the SEO go through this check list. In total, it’ll cost less than $500.

1. Signup with all related forums. Put your site in the footer links and go through answering product related questions on a weekly basis.

2. Create a free OSCommerce and Zencart template related to your parent niche (if you sell CDs make a music template), insert your link on it and distribute it on template
directories and their repositories.

3. Create an articles section on your site and put in a form allowing people to submit articles. Email hobby blogs in your niche asking to use some of their particularly good posts in exchange for a link back in the article. This will make them aware of your site and they might even link to you in future posts when talking about a particular product.

4. Steal your competitors articles and product reviews and do article distribution.

5. Create a blog on the site and give out manufacturer coupon codes regularly. This will sometimes help with getting negative results. Post those coupons on item #1.

6. Put all your products in Google Products (froogle/base). This will sometimes help with getting negative results.

7. Browse Google Products for small ecom sites with no reviews and similar products and link exchange on a separate automated link exchange script on a separate page.

8. Make sure you optimize your onsite seo. I assume you know how to do this.

9. Download, convert to html, and attach all the product manuals to each individual product. Link back to the product on each manual. This will give you more pages for indexing and catch a lot more longtail keywords.

10. Spam the fuck out of Yahoo answers and similar.

11. Directory submit! It may not work well for other sites of yours but ecommerce sites are almost always welcome in directories.

12. Customize a nifty and unique toy style item with your logo on it and mail it to the most popular bloggers in your niche. Shirts and hats also work well.

13. If you have access to the products get a webcam and pretend to be a vlogger. Review the products and post them on all the major video sites.

14. Create autoblogs and link wheels.

There’s more but I think that’ll keep you busy enough for now :)

EDIT:
There was some confusion in the comments on what I meant by “Negative Results”
“negative results” or “negative rankings” are the results inside of the regular results that Google puts in.
Such as:
Video Results
Image Results
News Results
Product Results
Blog Results
They used to always appear above the regular results so we call them negative rankings because they’re less than #1. Now they tend to go between random positions. This term may change the older this article gets.