I will give my experience - even though I've only had my store open for less than a week.
Actually - I opened my store back in January - as soon as I had a name, because then I was able to get the URL I wanted... even then, I had to compromise a bit.
I worked the entire month of February, building up my stock, working on graphics and store policies... I probably did over kill on my policies - but having worked in retail management my entire adult life, and now moderating an active message board - I have found out that having easy to read rules and expectations written out in advance just protects everyone.
It is very easy to list items on Etsy. Most people will want to list everything right away... but the most views you get to your store is when your items are first listed. Someone told me to trickle them on there - so that's what I've been doing. I opened my store with 3 outfits, then I have listed one every day since. The only problem I am finding with that, is that two of my outfits sold with in 30 minutes of listing - so then my store loses views that day because my most recently listed item then becomes the one I'd listed the day before. Make sense?
Etsy is also a very busy place... it helps to have a good customer base (I think) and a way to advertise your wares - otherwise people don't know that you have an Etsy store and they don't know to look there for you.
A friend of mine from work has a store on Etsy - and she has been very helpful with advise... everything she has told me has really rung true. She told me not to expect great things when my store opens, because Etsy really isn't condusive to making a living like that... it takes a while to become established - just like any business. She said that it really helps to have your store featured by Etsy - however - considering how many stores are on Etsy - the odds of that happening are pretty scarce. But she is also selling in a totally different section than I am - she is in jewelery - and that market is very saturated there.
Hope this helps. Maybe someone with a more established store than what I have will chime in and give you (and me) some pointers, as well.
Good luck!!!
D~