OfficeSkills.org: "Telephone Etiquette"
Although this source is intended for a receptionist position, the insight given about how to take and make phone calls can be applied to any position. Please click on the link above and read the entire article. As you read, take note of any of the phone etiquette rules you have broken in the past and consider why it would be helpful to follow these tips from the perspective of the professional on the other end of the line.
Click http://officeskills.org/telephone_etiquette.html link to open resource.