I’ve drawn a lot of portraits, and I use many techniques from the Right Brain book. Actually, I was using them before I read her book. They are pretty standard techniques and they are quite effective. I highly recommend the Right Brain book to anyone who asks me about drawing.
The “lopsided face” thing is pretty common. The best thing to do is just keep looking at the drawing in the mirror, seeing what’s off, and fixing it. I swear, no matter how “experienced” I get with drawing faces, I still make them crooked. They seem to look fine to when I’m working on the drawing, but when I look at them in a mirror, they’re all whacked. If I don’t correct my drawing by looking at it in the mirror, I eventually will realize how off-whack it always was (usually after I’ve finished the drawing and it’s much harder to correct it). It takes time to really “see” the problem spots. So, doing multiple reviews of the drawing in the mirror while you are in the process of working on it really helps speed up the process of seeing where the out-of-whack lopsided places are.
Sometimes, however, you have to realize that since the face is not 100% symmetcial, reversing it (by looking at it in the mirror) will make it look “funny.” If you ever unintentionally flop a person’s photo, you might have noticed that they don’t quite look like themselves. So, sometimes it’s best to leave a little crookedness in your drawing—as long as it looks fine when seen normally—because humans are not symmetrical beings, after all.
When I am drawing from a photo, I often also do “measurements” of the face, which does help on the lopsided/crooked thing. I measure the width of the eye (usually) of the photo, and then find out how many “eye-widths” long are the nose, how many “eye-widths” wide are the forehead, and make sure that each side of the face in my drawing is as wide (or as narrow) as it is supposed to be. This “measuring” thing is also a time-honored technique.
My big problem is getting one side too wide compared to the other side. Also, I’m notorious for getting the jawline crooked—one side of the jaw is lower than the other. Crooked eyes are also a big problem if you aren’t really careful. But you get used to being careful, so eventually it isn’t a huge problem.
When you are making up faces from your imagination, it’s best to just know the “rules” of how many (on average) eye-widths each part of the face should be, do a lot of upside-down drawing and looking at the face in the mirror. But usually, drawing from your imagination (which not everyone wants or likes to do) should be preceded by lots of drawing from reference, either live model or photo (usually both—I don’t think it’s good to be drawing exclusively from photos).
The Chuck Close grid thing can be a really amazing learning tool, and certainly it’s great for blowing up huge images, like murals. However, I know of a whole subset of artist (usually pencil portrait artist, for whatever reason) who draw everything (and I mean everything) using a grid. There’s this popular (“junk art” I think) drawing book that preaches the grid, grid, grid, for everything. So these artists never learn any other technique. And frankly, when you grid something with small enough squares, you really aren’t learning a whole lot about drawing on your own—drawing freehand—so using the grid exclusively can become a crutch over time. Not only that, it is time-consuming (squares on everything all the time), and locks a person into only using photo reference, since gridding a real live human, while there are methods for it, is usually too much of a hassle. So, while using to learn the grid is awesome (it really is), getting sucked into using it 100% of the time is, I think, a really bad idea. (I only mention this because there are plenty of people who will tell you that “using the grid is not cheating!” They say this as a defense for using it 100% of the time. My answer to that is, if you have been drawing for years and absolutely cannot do anything without using the grid, your skills are severely handicapped, and that’s not a good thing.)