All of it has its origin in basic shapes. So draw cubes, triangles, cones, spheres and rectangles from different directions to get an idea of how to give the illusion of form in space. It's much easier to draw a face after you've blocked out how the head is constructed and its easier to draw the head when you know where the body is and its easier to draw a character on a background when you know how the background will work.
Everything bleeds into one another so you don't really have to put one facet before the other. That's why I think the fundamentals are so cool. They LOOK boring, sure. But the result is being equipped to draw all sorts of cool stuff.
As for someone who can explain construction drawing better than me go to fineart.sk and check out "Figure Drawing For All It's Worth" by Andrew Loomis. His approach is NOT the only approach, it's about the way he methodically explains the idea of construction if you aren't used to the idea.