TJ, Don't try to take too much rock with one flake. A little at a time works better than bearing down hard and risking snapping the point. Using ridges still applies too. Like cowboy said, stalled flakes are usually from working with rock that has not been thinned enough. One of the best things you can do is to practice notching big waste chips. That way, if you screw up it is no big deal. You'll have to be extra careful not to break the thin chip, but it will save you from destroying a point you've made. Hope this helps.
Jim