All right, I've put a new cover up--I get the feeling I'm not doing it right, because I'm telling Amazon to "publish" again every time I change the cover art, and I think I could just upload the cover art and be done with it. But I'm not sure, so I've probably cost them an additional fraction of a cent with all this. Sorry, guys.
Anyway, the concept here is lightning, because (spoiler alert!) poor Trang gets blasted at one point, plus lightning is fun and dangerous! But I felt like that on the original cover, you couldn't really see the lightning, so it was just a plain black cover with yellow lettering. What with the choice of font and the yellow color, the lettering reminded me of a Hardy Boys book from the 1970s, plus the thing was boring and far too sparse.
So I used some bigger lightning, I changed the fonts, and I made the title and my name different colors. I put a banner across the top, too--marketing always amuses me, because the goal with journalism and educational/reference publishing is to be precisely accurate, with as little room for misinterpretation as possible. Marketing's a whole 'nuther story, so I put "#1 in the exciting Trang series!" up on the banner so that people will see that "#1" and go, Gee, this book must be number one in something! It's silly, but rest assured that Trust's banner will say "The second book," not "#2"!
Anyway, now the cover looks kind of like a textbook, although maybe that's just the dimensions of the thing.
ETA: It's up on Amazon now. It still looks like a textbook to me, but at least you can read the title in that tiny 1" x 1" format you see when you put in a search. That's kind of an issue, I think--there are a lot of very beautiful covers that are just illegible when they're shrunk down so much.