If you like basketball, you can think of each trade as but one point in a game, and each trading day as but one game in a series. If you like tennis, for goodness sake don't think of each trade as match point. In other words, realize that your trading is truly a series of probabilities, a string of events, no one trade makes or breaks you. If you like golf, think of yourself focusing on a tight target as you imagine the ball arching up gracefully to go to your target, or seeing the ball roll along a path on the green to drop into the cup as you hear it drop, and then imagine your trades going in the direction of the probabilities right to your target as you pick up the phone and place the order. If you like baseball think of yourself swinging at each high probability trade forcefully and easily, always keeping your eye on the ball.
Some people think of trading as hunting.
The hunter goes out knowing exactly what he's hunting whether it's big game, or rabbits, or pheasant. He goes where the game is. He's got the right equipment. He quietly and patiently waits for his prey. When he sees the prey, carefully he lifts his gun and shoots.