What are the best practices to design user interfaces that are going to be used under direct sunlight?

I'm designing an application that will be mostly used under direct sunlight, and I would like to know if there are some recommendations or best practices to improve usability under that conditions.

Probably things like:

  • Contrast
  • Color palette
  • Dark background with white text (or the other way around)
  • Minimum font size
  • Typography characteristics (Serif, sans serif, font weight, etc)
  • Spacing between items
  • Minimum item sizes