To graph a slope, it's best to have the graph's equation already in slope-intercept form, which is y=mx+b. In this equation, m is the slope — often represented as a fraction and b is the y-intercept, or the point at which the line crosses the y-axis.
If the equation is in standard form ax+by=c, it has to be rearranged. If the equation is in slope-intercept form already, simply place a point on the x-axis at the indicated spot. For example, if in the equation y=2x+6, the y-intercept would be at (0, 6). Then, work out the next point of the line by the ratio of m. Because m in the equation is 2, the 1 is implied. The ratio is the rise to the run or the change in y to the change in x. The slope is positive, so it goes up by 2 for every increment of x. Therefore, the next point is (1, 8). Going in the opposite direction would yield the point (-1, 4).
It's also a good idea to have a table in which all values are written out and can be checked later. This is done by substituting the values into the original equation to see if they hold true.