My list is small, but growing, and I've had some pretty positive results from email marketing.
I think offering an incentive is a good place to start, for example, a discount for everyone who signs up.
Offer them something new, something they wont be able to find elsewhere, like exclusive peeks at new upcoming items, or exclusive promotions etc.
Promote it everywhere - have a link to it on your blog, your facebook, your message to sellers, your email signature etc - people can't sign up if they don't know it exists!
I wouldn't give up on it, people who care enough sign up to a newsletter tend to be loyal customers - in my experience anyway.
Most email marketing providers offer free plans, so you really have nothing to lose!
