During the PhD days, it is highly recommended to find a good mentor. If you are a woman and planning to have a family, finding someone with a family and career to bounce ideas around with is very important. If your own PhD supervisor is not that person, find someone else in your own department or at another university or industry.
Some friends of mine had PhD supervisors who were very helpful in finding postdoc opportunities that would chart the way for a successful academic appointment. Academic mentors are usually great for mentoring an academic career because that is their specialty, but they are not as apt to answer the questions about other options. Medical school, law school, management consulting, industry science positions, medical writing, technical specialists in law firms, research administration, science policy, college instructing, forensic science are a few of the other options out there for graduating PhDs.
Looking in hindsight, I feel that if I had searched for one, I may have charted a different career path. Perhaps not. Find someone in the career you would like and ask questions how they got there, their typical day, the pros and cons. Ask them any question about grants, career objectives, where to train as a postdoc, how to establish tenure, non-academic career paths, how they balanced the demands on motherhood and a science career.
People are very willing to answer these questions - you just need to ask.
"Finding a mentor" will be a topic for a future post...