When graphing polar coordinates it's important to remember that r is the length of the line, and x is the angle in radians, measured anti-clockwise from the positive "x-axis".

What I do is use values for x such as etc, and plot the r values that these give me.

When I have a good amount of points I then join them up. Remember your graphs will most likely be circles or spirals.

Also a graphic calculator is invaluable for graphing polar coordinates if you have one.