In general anticipation, micro-adjustments, & memorisation.
Anticipation is the ability to know where the next beat is with high precision without it being displayed yet just based on the intuition of the music & map flow. It's not something that comes overnight or even over several months. It's an comes from extended "brain-training" & pattern recognition in both spacial & audio aspects, due to being expose to a large dataset of past experiences in similar music genre & how they're expected to flow in general. This is also why "anti-flow" maps or maps that are designed deliberated with the intent to throw off players for more play counts are so despised in the community. Having this skills allows you to "read & react" stuff that's not shown to you. Useful for knowing when to blink & where to move in an ambiguous situations such as high AR or low visible area, which can save yourself frustration more times than you give it credit for.
Mirco-adjustments comprise of many things, but mainly the ability to quickly & accurately adjust small errors in timing & placement. Over-reaching & under-reaching happens all the time, it's pretty much impossible to hit every not literally exactly centered. To micro-adjust is to factor in how the over & under will affect the timing & duration of the next key input, to predict where that adjustment will lead the catcher to in the next moment or hit object. Having this skill allows you to read & react stuff that's shown to you with high accuracy & precision. Useful for achieving good combo streak & calm attitude in tricky maps & prevents over-retrying, which again save a lot of frustration. It can help you in catching good spins & odd converts.
Memorisation I think speaks for itself, sometimes you just have to get it in your head, mostly unavoidable for almost anything in life when the task is too new or too hard.
TL;DR musical-spacial intuition + neural-motor agility + brain-muscle memory = everything. All comes gradually as you play more. Hopefully not too broad for your question.