I practise, doing something exactly how you planned/felt in your head is challenging and rewarding. I practise turning a lot, especially in mud, you can always get better at turning.
I work in a shop and do shop rides, i always get asked "how do you do that", I then ask if they've ever tried or practised it, the response is usually a no.
Hilldodger raises a good point where it is an art rather than a science. For those people that are naturally amazing, it is an art, but us mere mortals do need to think about it somewhat. There is over thinking though, if you get the right idea, relax and don't panic, it normally works out nicely.