Open house before school starts is always a plus for me.
I request email addresses of parents as they sign in.
I hand out my contact information on a magnet. No question that it didn't make it home with the child. I also post 3 questions on the board and make sticky notes available. The questions are: What do you expect of your child in ___ grade? What do you expect of Mrs. ______?(the teacher) What can Mrs. _________ expect of you, the parent? Parents write each response on a separate sticky note & place it under the appropriate question... ANONYMOUSLY!! This tool is invaluable. I take the responses and type them up on our class website. Now it is public knowledge what the expectations are from the families and at the bottom of the list I add my own expectations. It's great for getting buy-in from the parents early on in support of your classroom. I've also posted them in the classroom to point out to the students from time to time.
Note: Now that I am not a self-contained teacher, I have gotten away from doing this some. I think I will return to it this year even though I am 4th/5th science & social studies with no homeroom.