Golden Rules

Speed

Make your application run fast. Speedy systems also reduce vandalism.

Intuitiveness

Try to make the application intuitive.

Choices

Limit choices.

Guidance

Guide the user as much as possible.

Testing

Testing a touchscreen application on focus groups will disclose the areas that need improvement. If anyone pauses in confusion for even a moment, think how to improve the application.

Source: Interaction Design Guide for Touchscreen Applications