One of the scariest moments of my teaching career was making my first call home. I was terrified of what the parent would say and nervous I would say the wrong thing. I found out I really didn't have anything to worry about. The majority of parents seem to be happy to hear from teachers and more than happy to help out as best they can.
Parent calls are very important to a good, functioning classroom. The best thing you can do is call home before you have a negative reason to call home. Positive calls establish your relationship with the parents. This way, if you have to make another call home, they are already familiar with you and won't feel intimidated by their first contact with you being negative. Meeting a parent, even over the phone, for a positive reason first can be a wonderful tool in your classroom.
There are negative calls home, despite our best intentions. If you say you are going to call home, actually call home. Empty threats are the worst thing you can do, so if you've said you're going to call home, you better do it. If you and a student have had an issue in class, call home as soon as you possibly can. One of you is going to get to Mom or Dad with the story first and you want it to be you. Teenagers have a tendency towards the dramatic, so what was a tiny incident in class has been turned into World War III by the time you get around to calling.
When I call, I follow a rule from my sorority days. When we were voting someone into office in the sorority, each candidate had to have a "compliment sandwich". A compliment sandwich is using a compliment at the beginning and end of the conversation. I start the conversation off with something good about the student, then address the reason for the call. After we've discussed the issue, I compliment the student about something else before ending the conversation. This works really well because some teachers skip the compliments. Sometimes, these parents have only ever heard how awful their children are. If all you ever heard was awful things about your kid, you wouldn't want to talk to teachers ever again.
Sometimes parents need just as much love and care as students. Hey, this parenting thing is hard work! And teenagers seem to be extra challenging. It's nice to hear that your kid isn't completely horrible from someone who is supposedly an "expert" on teenagers.