Know all of the moving pieces in your life. Know what role(s) they play. Often we lose sight of the importance or value of someone in our lives. It could be due to a lack of love, respect, appreciation, or plain ole unintentional oversight of the person. When we do that, we notice things are not quite the same once they are gone.
The most important piece in the game of chess is the king. If you lose the king you have lost the game. Don't lose sight of who your King is.