I have learned some great strategies for using technology in online assessments; stating what is required on the syllabus and/or being accomodating if it is not required.
I have learned some excellent tips regarding tweaking multiple choice questions. I already include a lot of critical-thinking scenarios to my questions, but could probably look over more of the simpler questions as well.
I learned / re-learned the terms for "formative" vs. "summative" assessments.