Guest: "I'd love to see the best way to maximize practice. Say you sit down for a couple hours each day study: where do you focus? How do you make it stick?"
Here is how I learned to draw. I put on an animated movie and pause it and try to figure out how to draw it. this is still something I do almost every day for about an hour. For figure drawing, I take out a master drawing and do a master copy on newsprint. I also do studies from comics. I find it easier to do studies from art. For me (and this is just a very personal opinion) drawing from life, or from photos is like taking a test. You find out what you need to study more of and you go back and study artist to figure out how they handled things, then you go and take the test again. If you only ever draw from life, you run the risk of just repeating the same mistakes over and over again and never improving. there are pros and cons to this method. At first, your drawings will be very unoriginal, but eventually you can break free and develop your own style. The other side of the coin is to be very fresh and original, but not "technically" as good of a draftsmen (never study). It's a very personal decision that each artist gets to make and I don't think one way is better than the other.