Starting a new drawing can be daunting. Staring at a blank paper still scares me even though I try to tell myself that there is nothing to be afraid of, that I am allowed to fail. I can only learn something here and the drawing I produce need not be "good"; it's just another step in the process. I have to make it a mantra of sorts because I'm not just trying to learn how to draw well, but also to change some aspects of my personality. I firmly subscribe to the "measure twice, cut once" school of thought, which can be something of a double-edged sword when trying to put down that first line. Doodling helps here because I can be relaxed and just, well, doodle, but at one point getting serious about drawing requires thinking and observing the subject that is drawn.
As part of me getting back in shape I figured I should put my training wheels back on and draw more with traditional tools. At least in the beginning. Good foundations come a long way. Back in the art school we were given some instructions on starting, so let me reiterate here some tips for approaching the work from the very beginning. Just will, paper and pencil will do.
Visual measuring, when drawing from life, is done using a pencil or any kind of straight stick. An arm holding the pencil is extended to primarily measure two things: the angles of observed objects in relation to the paper's borders, and the proportions, which come down to how the object's parts relate to the entire object, i.e. how many times a part fits into the whole (the simplest example of this is determining the human head - body ratio based on how many times the size of the head should fit inside the size of the body). This is also used for measuring the so called negative space in the composition, the negative space being, for instance, the distance between an object and the edge of a paper, as well as the space between all the objects that are to be drawn on one paper. The positive space are the objects that are being drawn.
The most important thing while drawing is placing the first line and visual measuring helps a lot here. If the first line is wrong, the whole drawing can go wrong. Digital drawing can alleviate this by letting you transform and move that line and even by resizing the canvas, but traditional drawing is less forgiving. If you erase the line too many times, you damage the paper or make too big of a mess, so trial and error is not exactly the best option. Also try drawing with a pen at first because you cannot erase the lines, don't worry about shading at all. Using visual measurement helps train the hand as well as the eye, it boosts memory and can even help relax a person doing the drawing. This part of the drawing process involves a lot of thinking and at first doesn't come intuitively.
Remember that "measure twice" principle? Here is where it comes in handy. Observe and think.
Other useful techniques that can help out when starting a drawing are the contour drawing - drawing the outline of an object - which trains the eye to notice details, and the linear block-in - drawing a boxy shape to encapsulate the object and then drawing smaller boxes within it, around the object's parts, until the block model produces a reasonably detailed simplification of the object's shape. I also found that drawing a lot of circles can bring about a shape of an object fairly quickly.
The point of these techniques is to facilitate practice and produce sketches, which can and will usually look messy and ugly. That is OK because the refinement will come later. In this case there's no need for an eraser that much because drawing a wrong line can help the next one to be placed better than the last one.
I am doodling every day and the results are in my scraps page of the DeviantArt account. You can check my progress there as well.