While many Magento SEO articles address on-page search engine ranking factors like headers and category titles, you may get a lot more mileage out of adjustments to your template. The Magento template defines the code structure of the page, and that page structure is very important to SEO. It is actually the reason that search engine optimization has “on page factors” in the first place.
SEO Modifications for Magento should focus on the template, making sure the Magento template used demonstrates search engine friendly – ness. I think that is the first, most impactful SEO effort you can undertake whren trying to SEO Magento.