This is what comes with knowledge of fundamentals and lots of market experience.
Knowledge of fundamentals are not necessary but it is useful for identifying some no-brainer trades. As with the ECHF long on Friday - can you forecast events like this with high certainty - nope (and if anyone tells you they can then they are talking rubbish and blatantly have an 'agenda'), but what you can do is quickly process the event and 'know' whether this represents a high probability trade.
Knowledge of fundamentals are not necessary but it is useful for identifying some no-brainer trades. As with the ECHF long on Friday - can you forecast events like this with high certainty - nope (and if anyone tells you they can then they are talking rubbish and blatantly have an 'agenda'), but what you can do is quickly process the event and 'know' whether this represents a high probability trade.