Heres a tip I learned a few years ago.

Teachers don't take the time or the energy to initiate an e mail to parents (unless of course there is a real problem).  But if you write to them, they are required to respond to you within a specific time period, usually 24 hrs. 

Create a task or event on your calendar to remind yourself once a week to write an e mail to your child's teacher(s).  Ask how last week went, ask about any upcoming assignments or tests, ask what you can do at home to support your child and his/her teacher,  and just see how your child is doing.

This way you'll stay on top of things before there is an issue and nothing should take you by surprise.