This comes from an email I wrote to a student of mine in first semester who's greatest difficulty is not knowing where and how to start a drawing. There are many approaches and this is but one, but it is one I have used with students for many years now. I use it myself in varying degrees, especially on those days when I hardly want to draw or just don't feel up to it. I call this Bad Day Drawing Technique.
Beginners are often overwhelmed by the complexity of what they face in the figure or anatomy. Even with eyes wide open, the mind shuts them to true observation and what essentially happens is that one is no longer observing or truly seeing, rather just looking.
If this is the case I suggest you follow these steps:
1 - take a moment to look and absorb what you are looking at.
There is no race or rush to hit the paper. I would rather see 20 sec of observation and 10 of drawing during a gesture than 30 sec of scribbling while madly dashing off in all directions hoping to hit something of which you have no idea what it is.
2 - get a feel for the gesture and reduce it to as few lines as possible.
Gesture is the feeling of the flow of the pose, the impression it gives of the attitude it projects. Start at the feet and grow it upwards or outwards. Don't just think of what it is doing statically: ie standing, sitting, laying down, rather of the feeling it projects / the emotion however subtle: fear, defiance, sadness, etc...emotions we call 'attitude'
3- mark or break down the proportions
Proportions are just relationships. Whether they are shape, or length or forms, they are just comparisons of one part to another to the whole. But you have to ask the questions to get the answers. In the beginning it may seem to pause your drawing, but it is necessary. If you were traveling through unknown terrain you would pause to ask yourself which way to go otherwise you would rush off in wrong directions. Same thing for drawing. you must stop and ask. No questions asked, no answers given, and the drawing is simply the visual answers to the questions you pose.
4- position the boxes
this requires a few things:
-that you are aware of the proportions of the boxes in the way they relate to the the parts they represent. If you are not aware or care it won't be right.
-you are aware of which way the planes (surfaces) are directed.
-you can actually draw and keep the proportions of the boxes consistent as they move through space.
5- Sketch in the skeleton
- if there is little time note first the places where the skeleton influence the surface (landmarks and joints). This of course requires a good understanding of the skeleton, attained only through repeated drawing studies.
6 - Pull the skin over the skeleton.
I suggest you work on each stage until you are confident with that one before moving to the next.
My experience has shown that this works. With dedication and perseverance I have seen some initially very weak students progress to high levels.
It's up to you.