As someone who's learning how to better graphically design book covers, may I ask what your process is in deciding the design for each book?
yes! posting my answer in case any authors are curious or disagree with my creative choices lol
in school i had to do tons of thumbnails for projects before starting to formally design anything so i try to start there — usually thinking through the images that stood out the most in the fic or the overall vibe of the work. when i started this whole cover project i went through a file i have that has all my epubs' titles + summaries (so i can keep track of what i have archived) and sketched out a few ideas for the fics that were freshest in my mind. more recently i've worked on paper since it feels better but sometimes i'll sketch something in my phone's notes if i'm in transit or something.
then once i have some sketches i like, i try to find images that resonate with what i want to do (century library, unsplash, the met and other art museums' websites, etc are all great resources). i like to keep images public domain or creative commons as much as i can just for peace of mind.
sometimes i have a new technique i want to test out which will also guide the type of image i'm looking for (ex. a new design effect or a book cover i saw at a bookstore that did something interesting that i want to emulate).
this is the folder for love song for the admiral with the different options i'd gathered:
and then once i feel like i have a good selection i go into illustrator or photoshop and start messing around until it feels right.
sometimes i export what i think will be the final and then when i look at it the next day or week, i hate it and want to start over. about half of the covers i posted in the first batch were actually V2s, and there are about 10-15 in my files that i've "finished" but don't want to put here because they don't feel as developed as i'd like.
as far as good resources for learning, just looking at IRL book covers is great; there's a lot that you unconsciously will pick up from seeing the text scale, image treatments, type/image balance, or colors. used bookstores or libraries are wonderful also because there's a greater variety between the trends that were popular when each edition went into circulation.
any graphic design book that goes over typography or the basic principles is a nice-to-have too; it's helpful to know the rules so you can break them or ignore them.
i hope this was helpful! happy to go into anything in more detail!