There isn't much to it if all you want to do is list your work and hope someone buys it. However, there are currently 1.8 million active sellers on Etsy and yo will be lost in the masses unless you work at it. It's a lot work.
You'll need to learn about SEO (Search Engine Optimization), social media, marketing and photography. This stuff matters a lot. If they can't find you they certainly are not going to by from you. When they find you and you have crappy photos your going to get skipped. You have to write good descriptions of your items.
Then there is the business stuff. You know book keeping, records, shipping, taxes and in some cases licensing. Where are you going to put the money when you get paid. How are you going to pay Etsy. Do you need or want a business credit card. How about a business bank account?
Depending on where you live shipping can be a real pain. Do you want to drive 20 miles to ship a package that you make $5 on. What about packaging materials. Where are you going to store all this stuff.
You need a lot of stock. 100 items seems to be some sort of magic number. when you get more than 100 listings you get moved up in the search rankings. You need to learn how the search rankings work.
There are solutions to all of these things you are going need to work out. It takes awhile to get it all going.
There are brands and logos to consider. You might want have a domain name or a blog.
The successful sellers work at it like anything else.
It is cheap $0.20 per listing for four months. Considering all the services Etsy provides this is dirt cheap.
I opened my store last fall, Got bad sick and could not get everything in place for Christmas. But even being new I still sold things.
By the time Thanksgiving rolls around next year I plan to have 120 or more listings. More if possible. Right now I'm loosing money big time. I'm spending lots of hours figuring out how to do this stuff. Without pay. But that's the way of it. When you start a business people don't suddenly beat a path to your shop.
There are a lot of claims floating around but very few real numbers are attached to them. There are people that have sales in the six digit range. These are few and far between. They may have started as one person but now they are a company with employees.
My Etsy Store:
http://odinstoyfactory.com