Draw two straight lines using your ruler, one along the left side of the paper (for your Y-axis), and one along the bottom (for your X-axis).
Write your bar categories along the bottom of the X-axis. For example, if you are making a bar graph about political parties, your bar categories might be "Democrat," "Republican" and "Independent."
Convert your Y values to scientific notation. For example, you might have 12 million members in the "Independent" category. In scientific notation, 12 million is 1.2 x 10^7.
Write the numbers from Step 3 along the left side of the Y axis, starting with the lowest number on the bottom, and ending with the highest number at the top. The Y-axis should contain evenly spaced increments from the minimum to maximum data values (for example, 1.2 x 10^7 to 3.0 x 10^7). The bottom left of the axis customarily starts at zero, but you can also start at the minimum value (for example, 12 million) if you feel that the graph would have too much empty space.
Draw bars for each category up to the height of the corresponding Y value.