Ask for things that are critical to your specific needs, e.g. freedom to attend the preeminent conference in your subfield which always gets scheduled in week 1 of the semester, ability to spend a week off campus during peak frog-collecting season, or similar things.
Ooooh, thanks for that suggestion, Porcupine. I hadn't thought to negotiate upfront for the conference that will be timed badly in the term for my dream job.
Yes, I just made a mental note of this as well, as I'd been stressing about a poorly timed conference in my first semester if I do get an offer for next year. Thank you!