Have you ever been in the middle of a drawing or painting only to find you've run out of room for a head, fence, or other important part? Everything had looked nice in the drawing as you put it on paper, but suddenly, it becomes obvious that the proportions are all wrong. The grid system can be tedious and often leaves extra pencil markings on the paper. This simple technique is a "halfway" solution that takes a little practice but can be used in any drawing or painting to get those proportions correct whether you are working from a photograph or live landscape.
Hold your pen or pencil against the photograph lengthwise and measure how many "pencils" the major feature of the photograph is across as well as up and down. If you are drawing a live landscape, hold the pencil out in front of you at arms length and measure in the air. Make sure that there after, you always hold it at the same distance.
Decide how many times bigger you want the figure in your drawing or painting to be than the one in the photograph or scene. Then figure out the ratio you will need to use. For example, if a barn is 1.5 pencils long and you want it three times bigger, it should measure 4.5 pencils in the drawing. If it is 1 pencil high in the same example, the height should be 3 pencils in the painting or drawing.
Lay your pencil on the paper and mark out the right length and height with little pencil marks and jot down your decided ratio somewhere so you don't forget. Begin to work on the drawing. When you add components such as a window, continue to use the technique measuring the photograph or landscape first. With a pencil, one you have the ratio established, you can use smaller features on the pencil for smaller details such as measuring number of "erasers" or "pencil heads" and then multiplying them appropriately in the drawing. For example, if the window measures 3 pencil erasers and you have decided that your drawing is double the size, you should sketch out a window that is 6 pencil erasers long.
As your drawing or painting becomes more complicated, you may get carried away with the fun and the details. Use the technique to go back and check important features or those for which the proportions look off when compared to the photograph or landscape.