Copy professional riders (except for the pharmacology). I'd say that the single most important insight I had, the one thing that in addition to meager talent allowed me to climb into the professional ranks, was the value of shameless mimicry. At the time I did this, very little of my idealized imagery came from actual live racing (a handful of spectator occasions in my area) or even filmed footage (Tom Simpson or the Milk Race or whatever). The brunt was still photos in magazines and newspapers, from which I would sort of extrapolate a full range of probable motion: you could not be in position 'Z' unless you had, milliseconds before, been in position 'Y', and before that 'X', so on.
I was very aware when I entered my first races as a 13-year-old that, even though I was complete crap, I alone among my fellow competitors looked correct. As I got faster and stronger, there was very little need to undo bad habits — for example, a bad set of angles in my action, or a bad posture in or out of the saddle. Even moving in and around other riders in the peloton was like second nature, right from the start, because those dynamics and etiquette could be fairly accurately interpreted from stills. Nowadays, with YouTube and DVDs and such, the process would be far, far simpler.
I work with a number of juniors now (as well as grown-ups), and no matter how loudly they bark I don't let out the lead until they look right to me. Mind you, 'looking right' has to encompass a range of skeletal awkwardnesses and muscular limitations, but for any given anatomy, there's economic and graceful version of that anatomy. Finding it early on permits, eventually, a complete expression of the native ability.