On graphing polar functions

I've been teaching myself Calculus II and polar coordinates are giving me the hardest time. I know there are two methods for graphing a polar functions, you can compile a table of values or you can refer to the Cartesian graph of the function itself. For $\displaystyle r =1-2 \cos(\theta)$ I have been trying the latter method to no avail. The problem is I don't know in what increments to label the x-axis for the graph. People usually say set $\displaystyle \theta = \frac{\pi}{2}$ and solve for $\displaystyle \theta $ and that's how you get your increments, but in this case I get funky answers. Someone please.