To establish causality you need to show three things–that X came before Y, that the observed relationship between X and Y didn't happen by chance alone, and that there is nothing else that accounts for the X -> Y relationship.

What is the best way to give evidence of causation?

Experiment. Randomized experiments are the best way to identify causal relationships. Experimenters control the treatment (or factors involved), randomly assign the subjects, and help manage other sources of variation.

What are the 3 criteria for causality?

There are three conditions for causality: covariation, temporal precedence, and control for “third variables.” The latter comprise alternative explanations for the observed causal relationship.