How can you draw the form of things accurately? Measuring is a big part.
There’s a variety of ways, but one of my favorites doesn’t require a ruler, at least for the measuring part. You use your drawing pencil to measure. Here's how you do it. (I used a vase.) Stand back from your subject. (I put my vase on my table and went around to the other side.)
Aim your body toward the subject. Hold your pencil in your hand and stretch your arm out straight, locking your elbow.
Now close one eye (if you’re right handed, close the left eye and if you’re left handed, close your right). Hold the pencil upright. Now, put your pencil in front of your subject.
What if your subject is too big to measure? Step back until until it fits your pencil. Remember this spot. You will make all future measurements of your subject from that place.
Now that you have the measurement, mark it on your paper.
Then go back and measure the width of the vase by tipping your pencil horizontal and putting the tip on one side and your fingers on the other.
Look at other subjects and practice measuring the height and width with a pencil, then marking them on the paper.
If you have some time to kill, find a set of cupboards in your kitchen or office. Measure the height and width of the whole set and mark them as you go. Then, going from left to right, measure the width of each individual cupboard door and mark it, left to right, on your paper. Then go back and from the top, measure the height of each individual cupboard and mark it. Take a ruler and connect the lines. You'll have accurate 'bones' of the cabinets.
Use this technique on anything!
Next week: Form: drawing a perfect (or pretty darn close to perfect) vase