REPETITION
You will feel confident once you have spent months or years repeating the same pattern over and over again, day after day. After a long period exposing yourself to the same asset class (preferably one single instrument and one single timeframe), you will start to interiorize what you see on your charts or your trading platform, whatever kind it is, and intuitively will recognize your valid set-ups. And you will also be aware of when your setup is invalidated by an unexpected change in the market structure and you need to cancel a trade anticipatedly. Months or more often years are required to complete this stage.