1. Don't yank on it relentlessly till you run out of cord. Use a short upward motion instead, paying attention to where the cord rubs on the grommet on the cover.
2. Pull very easy first to engage the pawl and they won't break as easy.
Something else you can do is pick up a Killer RC stainless steel pull start kit. I never broke anything in my pull start the whole time I had my Baja.