Don't allow anything to surprise or shock you
This is the advice Vivekananda's father told him on his deathbed. Our brain is basically a pattern recognizing and prediction system. The brain continually makes predictions based on past experiences and beliefs. When our predictions, beliefs, expectations or assumptions go wrong, we find it surprising or shocking. When we fail to adjust to the new reality*, we might be swept away by the shock wave losing our balance and end-up creating a cascade of damages that may take months, years and sometimes even lifetime to correct and recover. When we find ourselves in a place of surprise/shock, it is better to take time to breath and find a balance and clarity of the mind first, instead of rushing and acting out.
Don't take anything seriously or personally
There is no other serious disease than seriousness and taking everything so personally. This is the root of all fights and wars in the world. This is the root of all our misery and suffering. This is the cancer that continues to corrupt and destroy humanity. As we struggle hard to eliminate these symptoms, we continue to feed the root cause of ego-building in every aspect of our life and society. We make things as a big deal and become so self-absorbed and self-righteous. Humility and a sense of humor are good antidotes for this dreadful disease.
Don't do anything under the influence of emotions
When we are emotionally hijacked, whatever we do (our action, speech or thinking) is bound to be unskillful. If we try to control and suppress our emotions, we are bound to fail. Our success depends on learning to relax first and then bringing clear awareness of our emotions. In the moment of anger and aggression, fear and panic, just remembering to breathe can be a lifesaver.