My writing recommendations may upset some writers with more literary aspirations, but at the end of the day, Tapas is a platform where casual readers come to read accessible popular fiction, and being able to grab the audience and deliver a tight story is a really useful skill here. One thing every successful creator on Tapas I've ever spoken to has said is that Tapas is a place for potboilers, so here are books to teach you to write an excellent potboiler, whether it's a novel or a comic...
Save the Cat! - Blake Snyder (or Save the Cat Writes a Novel - Jessica Brody) - Being from an art background and with a degree in English Literature, I really struggled to learn writing on a "nuts and bolts" structural level, and I can't thank this book enough for teaching me how to make a story that actually functions.
Save the Cat! will teach you how to create very functional generic popular fiction story structures. It lays out roughly where in your story you should be hitting particular story beats and what those storybeats should be. Having the structure in place really helps for writing scenes with purpose rather than just having your OCs milling around being cute. The original book is about screenplays and uses Movie examples, so I think it's better for comic creators, while "Writes a Novel" gives novel-focused examples and even breaks things down into page count.
Romancing the Beat - Gwen Hayes - Like Save the Cat! This is a book about formulaic story beats; in this case, the ones specific to "kissing books", so Romance, GL and BL writers, or just anyone including a Romance subplot could probably benefit from giving it a read. It's nice and short, too!
For comics and art, the big ones I always recommend are:
Making Comics - Scott McCloud - This is the most valuable book on making comics ever made. Like, it's basically a must-read. I don't really know what else to say. If you're making a comic and you haven't read this, GO AND READ IT. RIGHT NOW.
Drawn to Life - Walt Stanchfield - This legendary Disney animator was given the task of training up a bunch of newbies to revitalise a failing animation studio. These are his lecture notes and collected wisdom. Considering that those newbies then made The Little Mermaid, sparked the Disney Rennaisance and then made Beauty and the Beast, Aladdin and The Lion King.... yeah, I'd say he was pretty successful and that there's a lot of good stuff in those notes! This isn't a "how to draw" book; it's really more like... philosophy of acting through art and animation, so it's best for a more advanced artist at graduate level, so if you're in that awkward spot where you're kind of approaching or just about at pro level but your work is still a bit unpolished or awkward feeling somehow, this is what you need for that level up. Best read a chapter or two at a time, with time to digest in between.