Other than "So how is she doing?"
I tend to find the teacher takes the lead anyway and tells you most things you want to know, but I find myself saying "No I think you've covered everything" at the end and then usually think of another question as soon as I've walked out of the door.
Generally I don't have any major concerns as my daughter seems to enjoy school and is bright, but I wondered if people had any tips as to how to get the most out of a ten minute chat with the teacher. Also others might be feeling the same.