Avoid using cellular or cordless phones as they are easily picked up on a scanner. Use someone else's phone or a pay phone to make calls that must be kept confidential. Add a password to your voicemail and answering machine. It can be as simple as turning on a certain light in your home. You can also call a neighbor or friend every day at a certain time, or have them call you.
Home security is very important.
Consider changing the locks on your doors. Keep doors and windows locked whether you are home or away. When at home, never automatically open the door at the first knock. If you have children, install a second lock high on the door so they cannot reach it. Be alert for any unusual packages mailed to your home or office.