Don’t beat a dead horse. There is no hope long before there is no hope. Fighting on and trying to make futile things work out is a waste of time. Resign and get on with something new. This is true in chess, in business, in relationships and in much of life.
Pieces can - but do not - suddenly take on superhuman properties. If you have blown a game by losing a piece (or three) with no particular plan, then scan the board. If no options exist, resign. Pieces do not suddenly take on superhuman properties where you can beat an opponent that is way ahead. Playing on for some miraculous win is foolish. Go back and review your mistakes and then avoid them in a future game. Then, your pieces might get superhuman.
Too good to be true. Chess is a game of deception. But people make mistakes and sometimes things are too good to be true.
Keep them staring down a gun. I do some ski instructing and with new skiers we always tell them don't look at a tree or a rock if you want to avoid it, look where you want to go. If you stare at a tree you will go right into it. Don't underestimate the value of a simple checkmate setup. Beginners tend to want to win with the simple checkmate setup, experts use them to create tension on the board. Keep your opponent staring at the checkmate scenario and then steer them into a tree.
Home runs (wild complex checkmates) are fun but ... they result from careful moves. Don't fall wildly in love with a possible outcome and lose sight of making those careful and required moves along the way.
Don't forget why you are winning. There is a strong tendency to let one's guard down and the mind to wander when ahead. Great companies when ahead keep their winning ways and stay close to plan. Great boxers are great finishers, when they wound their opponent then they finish them off through continued concentrated effort.
Math is real. In chess pieces have associated values (e.g., pawn is 1, a rook is 5, a queen is 10). There are super moments where you can go down in value to win the game but far more often you will go down in value and lose the game. Don't delude yourself, do the math. In business watch your income statements and in life your budgets. Do the math and know your real position.
You can move backwards. Moving backwards is often an option (in chess, relationships, business, etc). Forgiveness is good. In chess, sometimes the best move is backwards but people get locked into moving forwards (even as plans unfold badly). Knights, Bishops, Rooks, Queens & the King can move backwards. Pawns cannot so move them wisely.