A couple of auctions running here and there, or ending at peak times every day or so can help get traffic to your listings and store, but I would keep the majority of stock as BINs. Not too many buyers have the patience for auctions these days, and while very popular items can still do well, ma lot of auctions these days are lucky to get a bid (even with start prices well below value).
Stock photos are ok as the galler picture, but I highly recommend having a scan or photo of the actual item for sale both in the gallery and listing. People like to see the item they'll be buying, especially when it's something like a secondhand book.
I'd also suggest larger font for your description text, my personal opinion is that pictures and description of the item for sale should dominate the listing page, not things like Terms of Sale.
Consider grading components of your items that other seller's don't, as it can help to increase buyer confidence in the product, as well as help to avoid any issues where the buyer is surprised / disappointed about something (it may seem over the top, but I often grade the case and the insert with things like pre-owned DVDs, CDs etc, and of course making a note of any noticeable flaws, even if just a barely visible crease at a corner (you never know when a customer is a finicky collector ๐ ).
