Try not to use shortcuts for passwords and access codes like keeping written passwords available within vicinity of the computer.
Make certain to lock all access to computer or mobile devices with a password.
Regularly change passwords, preferably several times per year.
Require regular updates of operating systems and create a way to verify it has been done.
Report suspicious network activity immediately.
Be aware of how to recognize and avoid viruses and malware.
When using mobile devices, turn off the "Bluetooth discoverable" mode.