It is an impossible to create a system free of errors.
Slide 2
There are a number of ways you can prevent an error.
Extensive Testing
Thinking ahead
Training
Usability Research
Clear Guidelines
etc
Mistakes Will Be Made
Slide 3
How to Handle an Error
Create a message for the user and include the following:
An explanation of what the user did
What the problem is
Instructions on how to correct the problem
Information is written in plain language
An example