What to read on learning to how to write

For the past year, I've been struggling to improve my writing skills and I've gotten better, but I'm still not satisfied with the stories that I've written so far. When I wrote my first short story, a 40K YA romance, I didn't know anything and I hadn't read many books on the craft of writing. Months later, I've read a lot more more books and written thousands of words.

I have three drafts of romances: two contemporary and one YA. Another two unfinished drafts of about 16K each. I've read read approx. twenty-five random books on the craft of writing fiction. Most of them had some useful information. The books that I liked the best, at the moment, are:

• On Writing by Stephen King
• Revision and Self-Editing for Publication by James Scott Bell
• The Well-Crafted Sentence by Nora Bacon

What writing books have you new writers or authors found most helpful?