There are many SEO strategies that work for content sites but not Ecommerce sites. For example, commenting on blogs and using bookmark sites would be bad taste. What are some good ways to gain PR for an Ecommerce site?
go for Press Release and Blog post or blog review and also forum posting. it will be so much helpful to so many Ecommerce sites. i already optimize 10+ Ecommerce site. i have so much experience in that.
Article submissions always seem to help and like robertgallagher said you should probably submit a few press releases. I also recommend submitting to Yahoo! Directory, and The Open Directory (Dmoz) because even though Yahoo! charges $299 a year for a single listing, it can greatly help your serp positioning. Then I would use a good semi-automatic free directory submitter for my main site and maybe create a blog to help target different keywords. You should preform keyword research first though, otherwise you may get listed for low or no traffic keywords/key phrases and ultimately waste your time. I use the Golden Cash Compass for most of my keyword analysis because it's fast and free.
Article submissions and Press Releases are very effective. We launched our Press Release through PRWeb.com and in one day we had over 2,000 reads, and 205 clickthroughs, which is a astonishing rate. There are many free Press Release websites that you can post your press release to, which helped us tremendously as well. As far as articles, this is the one most don't think about doing. This gives you an inbound link for each article on each site you post to, and if someone else picks up the article, that's another link. Just make sure that you link with an effective keyword. For example, instead of a link that says softwaretech.com, we would want our link to say "HR Software" and have the link point to softwaretech.com. This will get your site ranked higher for the keyword HR Software.
There are social network/bookmark sites that are specifically geared towards 'selling things'; e.g. wists, kaboodle,thethingsiwant. You need to check out the policy of the different sites, though, some encourage ecommerce sites to add their products, some regard it as spamming.
Do you the regular stuff: on site the why it should be and off site - backlinks. It works the same as regular website.
I don't think the strategy necessarily has to be different between an ecommerce website and a content website. In the end you just want quality links. The only real difference is that you might have to be slightly more careful with the ecommerce website as it can't afford to be banned or penalized.
Answer questions on social communities, Yahoo Answers, and various forums in relation to the products you carry. Unless you're pimping and pushing the product, people don't mind a link drop showing who you represent after giving honest advice and answers on a related topic.
I love marketing e commerce websites I honestly don't know why but the best thing is go to different communities and posting and helping people out and building a reputation and it always work with a charm for me.