explain three cyber security best practices

From the global perspective (a corporation that has IT spread across the world, US government/military, and worldwide cyber vigilance), explain three cyber security best practices, what they are, why they should be used, and how to use (not expected to implement but be able to explain).  I will understand if you include in this answer the best practice(s) that you have noted in the above question(s). But also try to look at it from the global perspective and any unique need. Number the best practices as i, ii, iii, etc. so that I can clearly identify them.