Chess was not yet invented when...
"Our first and best victory is to conquer self." -- Plato

“We are what we repeatedly do. Excellence, then is not an act but a habit.” -- Aristotle

Ah, self-control/discipline and persistence/perseverance are the keys to success (after honoring God...meaning a poor, humble person [a person of any background, creed] who worships God is exalted way beyond an educated, rich person in a suit and tie who flies about in a private helicopter but refuses to give glory to God). Successful people have many scars from paying their dues, overcoming obstacles, and not giving up after lessons learned the hard way.

Getting back to chess...
After the opponent has just made a legal move...consider his/her next move immediately. (Even though it's your turn, do not think about your pieces. Instead, think about what the opponent will do next.) Ask yourself "Why did my opponent do that? What will my opponent DO NEXT?"

It takes a bit of time to find the best move in most positions. After you've thought about all the possibilities for both sides, compared potential sequences, used process of elimination, and found what looks to be your best move to make, pause.... do a final safety search before touching your piece. Ask yourself "Is this move safe? If I do this, what will my opponent DO NEXT?" Always know what your opponent's replies might be before it happens.

In the game above, Black did not do a safety search. Black omitted considering White's next FORCING MOVES...both Check and Capture, as well as FORKING moves...one unit attacks two or more opposing units/key squares simultaneously. Simply considering all ADVANCING moves where the opponent can come forward into your territory can prevent lots of problems before they arrive. Black just assumed the position to be harmless, and never considered the advance of the White knight above. Strong chess players have self-control...consistent habits...and consider what the opponent will DO NEXT.

"Don't play HOPE chess." -- Dan Heisman (Everyone's Second Chess Book)

"Know thy enemy!" -- Sun Tzu (The Art of War)
"We have met the enemy and he is us." -- Pogo (comic strip) "Haste, the great enemy." -- Eugene Znosko-Borovsky (How Not To Play Chess, Dover Publishers)