...Since anything I post has to necessarily come well after I've drawn it. One of the many great mysteries of the time/space continuum.
Another mystery is why I'm having such a difficult time hitting female facial proportions and placement on the first pass.
Actually, no mystery. Besides forcing myself to draw larger more often, I think a good part of it would be to simply not worry about constructing the individual features, the rendering therein, and just simplifying the shapes, drawing everything with a quick, decisive line; any construction lines, feature placement, or expressions especially. Should probably be the same approach as to doing mech design: Quick outer frame sketch first to establish dynamic shapes, then going in with whatever detail afterwards. Otherwise, it'll more than likely look too contained and indecisive once one starts fussing with rendering out where specific features go rather than how balanced the overall thing looks from a quick glance.
I think Shiyoon, Gennady, and Claire Wendling have the right idea: Forget erasing, just restart. Redraw the hell out of it, over and over, until you've not only loosened up with your drawing in general, but also are able to hone in on what shapes, perspective, and composition looks best after having hashed the same thing out several dozen times over. This helps with technical proficiency, as well as breaking one out of their shape/design/posing comfort zone.