Establish a schedule (make it a habit):

Establish a specific date every week/month/quarter to make a full backup for your data. Don't leave it to be occasional.
In our busy days, occasional tasks never accomplished.

 Backup before any new installations:

Whether you are upgrading new hardware, software, purchased a new notebook or even changing office location, it's always better to have a full backup before you move to a new step. Upgrading & moving to a new location/equipment sometimes cause data loss due to unpredicted accidents or even because of compatibility issues.

 Always Store copies off-site:

Backups are only safe if stored in different physical location than the work site. This is vital to your data survival incase of fire, flood or theft.
This ensures your data is not lost with your office equipment (god forbidden).

 Rotate your backup equipments:

Never use the same equipment repeatedly, if it fails you will lose all your data. Using different hardware in backups ensures that you will have more reliable data copy to restore.

 Always store your backup in a secured encrypted form:

Backups are portable by nature; you must make sure that your data can't be read if fallen into wrong or unauthorized hands and that you only can benefit from the backup.