Make some time daily to think about interactions that you've had that day. Don't necessarily draw conclusions. If you take up a natural interest in the chain of events of human behavior, you'll start identifying various events and how they correspond to emotions/etc in context.

Also, observe what other people do, decide if you want to act that way, and then try it yourself.

IMO the best you'll get is a distribution of probabilities for what a particular event means, so don't expect hard and fast rules, but sometimes that's enough.