Hi all!
Just thought I'd mention that, for my bestsellers, I've been having success editing the listing to sell quantities of 3 or 4 rather than just one item. I find that when I do this, people will purchase 2 or 3 at a time. This is also great for large influxes of traffic, like a front page feature, Heartsy deal, or holidays, that you can't always plan on.
This may be common sense but I just started doing it after a year here and find it to be effective.
<3
Andrea