Writing for Tangled Fiction has taught me a lot in terms of character and plot structure, but also self-discipline. The only time I'd ever written under a deadline was when I'd gotten my editor's notes for Parallel, my short story that was published in the Rebel Moon anthology, and that was a piece of cake compared to TF deadlines.
Twenty-four to forty-eight hours is not a lot of time to come up with something out of the blue, especially when it has to match what's already written. And if you aren't in a writing mood, it's that much worse. I'm all for stepping away from the manuscript, distancing yourself until you're in a more relaxed state of mind and you can let the creativity flow, but sometimes that isn't an option. Sometimes you're faced with a deadline. And if you aren't burdened by deadlines now, someday you will be!
I've written things that have come off as harried, and I've written things I've been much more proud of. I wish that I had some magical piece of advice that would give you exactly what you need to prevail in the face of evil thought-crushing deadlines, but I don't. All I can say is that deadlines don't have to be damning. Do not fear the deadline! But I think it's a great idea to condition yourself now so that when that five or however-many-page editorial letter comes, you're ready for it. You can do this. You can write something great even when your brain says you can't.
And if YOU have that magical piece of advice, I am so ready to hear it.