Use a ruler to draw a diagram on a piece of graph paper. Draw six vertical lines to represent the six strings of the guitar. Draw six horizontal lines to represent the nut of the guitar, plus the first five frets.
Draw black dots on the frets and strings that should be held down. For instance, if you are drawing a chart for the chord A, you would print black dots on the third, fourth and fifth vertical lines (counting from left to right). Each of these dots would be located between the second and third horizontal lines, meaning that these strings are held down on the second frets.
Draw an "X" at the top of the chart, just above any strings that you do not play in the chord. For instance, if there is a chord in which you do not play the first and second strings, you would write an X above the first and second vertical lines.
Draw an "O" above the strings that should be played open. "Open" means that you strum the string but you do not hold down the string with your fretting hand.