The only thing I can say is that I have been using ableton for about a month now, and the warping gets much easier with practice...
Also try changing the warp mode from "beats" to "complex" for better quality.
Actually, I didn't see any mention of that method on the lessons, and most of the djs I saw warping do the zoom out/zoom in thing which is what I'm trying to avoid.
I didn't have much trouble with warping, but as soon as I started doing it I realized that there is a big difference with music from a digital medium, like a promo cd or an mp3 bought from beatport, and a vinyl rip.
With vinyl rips, it's not enough if you set a marker at the beggining and another ...