Should be SKETCHING, not drafting, as sketches are made for ANY type of drawing, drafting, you name it.
It's as easy as it gets, one cardboard box, some extra thick cardboard from another box, a mirror, and a piece of glass, or transparent acrylic.
Cut the cardboard, glue it, and you've made a Drawing Machine, with a 2-way glass, where you see the scene in front of you, and the paper where you draw!
Draw the lines, as drawing on a window, and you are both drawing, and gradually learning to imagine that same glass in front of any scene, one day.

Thanks for the rectification about drafting, rimar2000 :)
Also, Kiteman, here's the actual Illustration, from the 1923 "The boy mechanic" book available on the Net via Project Guttemberg.

Step 1: I Assume You Know How to Draw a Line...

I assume you know how to draw a pair of 45º lines, using a 45º set-square, that you know how to cut Cardboard, and what diagonals are;
Because you have to cut a pair of these shapes, in order to glue them into the inside of the box.

Step 2: Cut the Thick Cardboard

Here it is, a simple cut, of 2 45º lines, out of thick cardboard, and you cut 2 of these, using just the center part:

Step 3: Glue the Side Plates

See how the 2 pieces go?
they are glued right side up, the right angles against the corners, the 45 degree angles up, and the edges that will sustain the mirror go up, away from the back side of the box.

Step 4: The Mirror Lies Down

The mirror lies down, that is, the mirrored side is down, and you see the green back side, up.
I use a Glue gun to fix the thing, after I glue it with just plain UHU. A mirror is a heavy piece of glass...
Note that a space is left to the front of the box, you have to put your hand on the box, later.

Step 5: Cut a Square, Up Front

As the top of the box will be closed with thick tape, in order to give rigidity to the thing, you set the points where top and the bottom of the mirror are, and mark a 90º line out of those, out to the front, so as to cut open a square portion on the front and top of the box.

Step 6: Two Diagonals

Where will you peek, in this box?
This is, in essence, a Periscope with a see-trough part, so the bottom and back part, where the remaining 2 45º ramps are, will have a round hole, about 4Cm diameter, cut, and the center of the circle will be set by drawing back the lines, so you'll get another square, bu this time, just use the corners to draw those diagonals, to find the center of the peeping hole's circle

Step 7: The Peeping Hole

With a compass, draw a circle, and then cut it out.
Real simple like.

Step 8: The Acrylic Goes Here

Turn the box upside down, glue the Acrylic rectangle, like you did the Glass one, use the Glue Gun, turn it right side up, again, it should look like this, note the glue gun's glue, on the edges.

Step 9: The Paper Goes In..

Here you can see how you insert the paper, it should be put into the box, and then, it can be folded so as to hang on the inside, and any means of holding it will do...

Step 10: Fold It, Tape It

Fold it, tape it, it's just about ready...

Step 11: What You See, When You Draw

This is the actual image you would see, my veranda's window open, some clothes hanging, not artsy, but it shows it works! :D
As this is a 2-way glass, you can also see a hand, and since your eyes are far better at double lighting than ANY camera, you can draw all those lines, until you have a sketch.

Step 12: 13 - High Contrast

Adding some Gimp magic, you can see more clearly the hand and pencil.
Have Fun!!!

Step 13: The Box!

Here it is, and of course you can do much better, with carpentry skills, and wood, but it works, anyway you make it! :)

Step 14: Final Notes on a Scheme

Here's a scheme for you to follow, you can see how it works, a periscope with a see-trough glass, and how the thick cardboard plates are put, so as to support both the mirror and the Acrylic plate.

The Laser cut gizmo is available here:
http://www.ponoko.com/design-your-own/products/draughtsman-learning-aid-5073