Draw a horizontal line. Align the protractor on its middle, with 45-degree angles on both sides. Mark the spots over the protractor. Draw two equal-length straight lines toward the spots and connect their top ends with a third line to form an upside-down equilateral triangle.
Add taxa by drawing lines within the triangle, starting from the right side. The branch and the taxon lines must form right angles. Erase the top and left side of the triangle, as well as the initial horizontal line, when you are finished with the taxa lines.
Add smaller lines for subdivisions near the end of an existing taxon line. Again the new line must form a right angle with the taxa line, parallel to the branch, to maintain a balanced look on your cladogram.
Write down the name of the species on the tip of each corresponding taxon line to finish the cladogram. Mention the ancestor -- theoretically at the bottom of the branch -- with the cladogram's title.
Draw a short horizontal or vertical line, depending on the type of cladogram you want. Form a Greek letter "Π" on the vertical cladogram, or an angled C on the horizontal graph. Design additional lines within the letter if you need to depict more than two taxa.
Stop the cladogram's lines when you want to mention the taxa. Add their names and continue drawing the lines.
Create smaller "Π" letters or angled Cs for subdivisions. Make sure all splits on the cladogram face the same direction.