In chess, as in life, it is foolish to wait for your opponent to make a mistake. You should not wait for the quintessential moment to reveal your potential because it may never come, or it may arrive too late.
Also, in chess, it is always important to see the bigger picture. No player plays to save every pawn he or she moves or all of his knights and bishops. Players get them killed or sacrificed. The sacrifices made are to be looked at as stepping stones toward victory. In chess, as in life, most of us do not sacrifice enough for more significant payoffs.
Also, failures are your best teachers, because you tend to learn more when you fail. In chess, you have to take a chance to know if it is the right move. In life, people come into our lives only to leave, and if you depend on them for happiness, you will fail.