I don't know about rockstardom, but to be at least moderately successful I'd offer the following:
1. Don't let coursework get in the way of your professional engagement and networking. The most successful grad students in my program were ones who made attendance at department events (guest speakers, job talks, chair-grad students meetings, etc.) and participation in professional activities a priority; the ones who were always "too busy with work for classes" (or worse -- TAing) generally haven't gone too far.
2. Attend conferences early and often. Ideally, go to one or two of the big ones (especially APSA) to observe what goes on as soon as you can, well before you're ready to start presenting. Pay out of pocket if you have to -- "I never went to conferences because my department didn't fund grad student travel" isn't going to impress a search committee.
3. Don't be obnoxious. You never know who can help or hurt your career down the line.
4. Learn how and when to say no.
5. Don't expect professors to "hold your hand" through the PhD and professionalization processes -- it's up to you to figure out when you need and ask for help, advice, and favors.
6. Never, ever piss off the department secretaries.