First you need a robust trading plan.
But then, to become a successful trader, and inparticular, a successful Day Trader, where existing in the moment is the name of the game, it is essential for the person to get used to, and feel comfortable with feeling uncomfortable in the moment, without failing to enter the trade in the first place, or bailing out of a trade early.
All of my intraday trades make me feel a bit doubtful, but sure enough, more often than not, they continue to come to fruitition.
I sometimes get hunches that tell me to bail out now, typically for a small profit - which is better than a loss or breakeven afterall. However, more often than not, i will then see the trade move fuurther into profit - which i should have caught more of. So getting used to absorbing this type of discomfort while sticking to the plan, is a must in my opinion.