I'm pretty new here, but I can definitely say that the difference in sales between about a week ago, when I was listing several days in a row, working on tresuries, posting in forums, etc I had several sales in a row. I was getting daily sales or even two sales a day, which is good I think for a new shop.
This week, I have been busy and have only made one sale. I think that will just be the way it is, some weeks will be better than others, and if you have the time to promote yourself and your shop, do it as often as you can.
Tamara