I second everything said above.
We opened back in 09' and went 4 mo. with no sales until we figured we had to do something different. I was very serious about making this work so we closed so to speak while we researched the ins and outs of selling here or anywhere online. Learned alot about SEO and how it works, learned how to take pictures(spent weeks on this), spent many hours in the forums looking for tips, advice, success stories and what they did, read many articles from Etsy success and reinvented our products, made sure that we had well over 100 items to fill our shop( I know this may be unrealistic for some, but I seriously did nothing else for 8 mo) Opened again in late Oct. 10'' and have done pretty good for just starting out....I am very happy with it. I still get excited over each sale and am always interested in what the buyer has picked.
You'll need patience, be willing to adjust as needed, willing to put in many, many hours of researching....my husband has become an SEO wiz :)
I don't know much about the jewelry supply prices or making it, but IF I was making jewelry I would use the finer materials. The cost for our supplies don't break the bank like some do, but we use the best for our particular products. I would assume this is important for those shopping for jewelry. Jewelry is very saturated though from what I hear. Think of unique ideas that one could not find elsewhere....even here...something that will make you stand out, that people will recognize and say hey that is .Thetwistedwire1978.
Stay patient, and like they said create,create and create:)