What can parents do to improve their communication with their children?
never discuss mistakes.
interrupt the child when he or she goes off topic.
turn off the television, radio, phone, or other distractions.
avoid difficult topics.

What can parents do to improve their communication with their children? There can be multiple answers for this question.

Never discuss mistakes - there's times when discussing one's mistakes is a good learning lesson, and on the other hand, it shouldn't be done at the time. Discussing their child's mistakes will only make the child think that their parents believe all their children do is make mistakes. Also, discussing mistakes will make your child behave better in life moving forward.

Interrupt the child when he or she goes off topic - this is a bad idea. If the parents don't want to be interrupted, don't interrupt the children. Interrupting them will only make them think that the parents don't care about what the child is thinking. 

Turn off the television, radio, phone, or other distractions - this is a good and bad idea. Sometimes, you can create conversation more easily while bonding over a show on TV, listening to music on the radio, talking over the phone, etc. If you really want to improve their communication with their children, I suppose this is the way to go. I wouldn't say 'improve' although. 

Avoid difficult topics - avoiding difficult topics will only make the child question things in life. There are important topics in a parents life that they must bring up with their child, whether it be safety, drinking, drugs, smoking, such and such. 

I believe that turning off the television, radio, phone, or other distractions will improve their communication with their children.