It not only helps you decide what you want, you also find out what you don't want. Become connected by going to meetings, especially small meetings like the Gordon Conferences, if you can. And once you're there, participate and ask questions so people get to know you. Try to get as many publications and make as many presentations as you can. Too many people start graduate school not knowing that they're interested in academia, where publications and presentations are very important.
Connections are very important.
Be careful whom you pick as an adviser. He adds that the organizational structure at Los Alamos initially attracted him because it provided the opportunity to take a multidisciplinary approach, enabling him to collaborate with electrical engineers, biologists, and high-energy physicists without crossing departmental divisions, as he says might be likely in an academic setting. Location was another reason for his choice of employer. Hjeresen says he fell in love with picturesque northern New Mexico, where Los Alamos is located, approximately 35 miles northwest of Santa Fe. Location was also a very important issue to neuroscientist John McElroy, who, like Hjeresen, did his postdoc at Los Alamos.