Use the ruler to draw a big plus sign on the graph paper and draw arrowheads at the ends of the rules.
Put tick marks at every place one of your lines intercepts the lines on the graph paper. If you have decimals in your data set, you may want to draw smaller tick marks in between each of the lines.
Draw a two-columned table for listing differences next to your graph or on a separate piece of paper. For example, if you wanted to graph differences for 4 - x = y and if 4 is in the x column, 0 will be in the y column; if -1 is in the x column, 5 will be in the y. Make sure to include at least a few negative numbers in your graph to cover all possibilities for your equation. Make a separate table for each equation you will be graphing.
Label the horizontal, or x-axis, according to the values you plugged in for x, and the vertical y-axis for the differences you got for y. Make the center point of the graph, or the origin, point (0, 0) and number out from there. Most likely it will be easiest to count by ones, but if it is more convenient, you can label axes by twos, fives, tens or whatever works best.
While it is technically permissible to number both axes according to different systems, it is not advisable since it can distort the shape of the graph.
Mark each point on the graph where the x- and y-values intersect. For 4 - x = y, you would go over to 1 on the x-axis, then up to 3 on the y-axis and place a dot. Repeat this for every value of x used in your table.
Use the ruler to draw a line connecting the points once you have plotted all of them. It should be a straight diagonal line. You can use this line to determine the value of y for any value of x or vice-versa.