You're in the right place for SEO help... most folks in here really want to be here, so no worries about ego bashing.
What are you planning on using for a platform to develop the site?
Tricky areas to watch out for on e-commerce sites include handling of duplicate content on category (list) type pages vs. actual product pages, particularly if they are nested and search result pages. You will definitely want to use your rel="canonical" tags.
As for the domain name, it's certainly helpful to include keywords, but it's not the end of the world if you don't. You're really developing a brand. Think of ebay or twitter even. Clearly, no keywords to be found.
If you're talking about the rest of the URL, then yes, make sure you work with a platform that has good SEO support: search-engine friendly URLs, meta title & meta description support, and a place to enter descriptions for your images at the very least.
That's a start... certainly ask if you have other questions!