An Accurate Eye | Learn to Draw by Learning to See Better
You can draw better, when you have an accurate eye. The best way to develop an accurate eye is by deliberately practicing discrete skills.
An Accurate Eye | Learn to Draw Better by Learning to See Better, by Darren R. Rousar, contains over two-dozen practical exercises suitable for everyone who wants to improve their visual accuracy.
Plus, you'll also get a 42 page supplement with additional exercises!