Are you in the habit of playing email ping-pong?
You know the game - you send someone an email message - perhaps you're trying to arrange a meeting or need some information. They send you an email back, you then reply to that email, they reply to that - ad infinitum until you manage to find a date and time that fits or you get the right answer to the question ... or not.
Over the course of several hours or days, you end up with a string of emails being bounced to and fro between you when you could probably have resolved the matter in a few minutes if you'd only picked up the phone.
When you receive an email - think before you type.
Would it be quicker and easier to pick up the phone and actually talk to the person, rather then spend twice as much time replying to their email and not getting or giving the necessary answer?
Talking to someone in person is so much better and more effective than indirect, impersonal email communication.