These are the worksheets introduced in Bruce's book Drawing in Three Dimensions. As described in the book: These worksheets will help guide further drawing practice. Each one of these is designed to emphasize an important concept in drawing correctly. They are designed to provide extra experience with aspects of drawing where most people need extra practice in order to eliminate common mistakes.
Each worksheet listed below is a link to a simple PDF file you can download and print as many times as you like for all the practice you want.
The more you practice, the better your drawing ability will become. Practice, practice, practice!