1. Backup before making any changes.Before you make changes to the information in your genealogy software or do mass changes to files make a backup of that information. Each genealogy software package comes with the option to backup the information in a separate file ... make use of it.
2. Backup after making changes.In this case I'm talking about when you've spent hours researching and entering in the information found. Before you head off to bed make a backup.
3. Verify your backups.You have religiously backed up your information but is it really backed up? Try periodically restoring a file or two from your backup. In addition to making sure that the information is backed up you will also learn how to do a restore. It is much easier and less stressful to recover your lost data when you aren't trying to figure out how to restore the information for the very first time.
4. You can never have enough backups.The one time you need to restore your information is the time you find out that your last (and only) backup had failed. So backup your information using different ways. Save it to local media AND also to a cloud-based service. Two copies are always better than one.
5. Keep copies of your backups outside of your home.Natural disasters do strike. So keep a copy of your backed up information somewhere other than beside your computer. A bank's safety deposit box is a great place to keep it safe.
6. Make doing backups a habit.Remind yourself to do backups by putting a repeating task or event into your calender. If you use Google Calendar have it send you a reminder by e-mail or SMS. In my case I back up my whole computer on the first of the month. If I've made a number of changes to my tree I back it up and synchronize it to my folders on Dropbox.
Murphy's Law usually comes into play when it comes to backups. The time you don't do a backup is when you have a computer failure or some sort of disaster occurs. So the final tip is ...
Backup Backup Backup