Conference calls are no different than any other business meeting. Preparation is a key ingredient to a successful meeting. All participants should be advised as to when the call will take place so that they can prepare for the meeting and be available at the appropriate time.
If you are the meeting leader, send out the meeting details, agenda and any appropriate meeting materials well in advance of the meeting so the participants can prepare. If you are a participant, make sure you have the meeting call-in details at hand before the meeting starts.
Take the call seriously, just as you would any important face to face meeting, and be sure to be prompt and ready when the time comes.