If I could pass on one piece of advice to beginning scientists it would be this: Don't be afraid to take on tasks that are not part of your official job description even if, at least initially, it appears you won't get credit for the effort. Of course it is important to focus your efforts on specific goals, particularly in the early stages of your career. But if you don't also develop peripheral vision you may miss important opportunities, including those that can help you with your primary responsibilities.
For example, early in my university career I was asked by my department head to chair the research seminar committee. In truth, the committee had long since ceased to function and no one wanted to take on the task of running it. I had been warned about accepting too many committee duties as a beginning professor, yet, I said yes anyway. I was given a free hand and a small budget to do whatever I wanted. It was not a lot of work and what I did was certainly not very original, nevertheless, my efforts resulted in three significant benefits to me:
They brought me in contact with interesting people in my department, my university, and beyond. They created an association in the minds of my colleagues between me and research in general, a real plus for any young professor. They allowed me to put into practice the old adage: "It is easier to say NO to something you don't want to do if you have already said YES to something you do want to do." In other words, after taking over the seminar committee, I was better able to deflect requests to take on other tasks that I didn't have the time or interest in doing.
They brought me in contact with interesting people in my department, my university, and beyond.
They created an association in the minds of my colleagues between me and research in general, a real plus for any young professor.
They allowed me to put into practice the old adage: "It is easier to say NO to something you don't want to do if you have already said YES to something you do want to do." In other words, after taking over the seminar committee, I was better able to deflect requests to take on other tasks that I didn't have the time or interest in doing.
About 10 years ago some of the Ph.D. students in engineering at Stanford began confiding in me that while they were interested in pursuing an academic career after graduation, many did not want to do so in the high-pressure and uncertain funding environment of Research 1 universities.
I decided to start a weekly 1-hour seminar to examine different kinds of academic institutions. In so doing, it became obvious very quickly that many of my students had almost no idea of how a university worked and what faculty did outside of the classroom and the laboratory. I expanded the seminar to include all aspects of preparing for, finding, and succeeding at academic careers in science and engineering.
This was another "extra" I did in addition to my regular duties and as in the past it led to additional opportunities.
Based on the seminar experience, I decided to try my hand at writing a book that would reach a larger audience. I asked my dean for a $15,000 grant to pay for a student assistant but essentially agreed to write the book on my own time. The 2 years it took me to do so turned out to be among the most exciting and intellectually engaging of my career. The book, Tomorrow's Professor: Preparing for Academic Careers in Science and Engineering , brought me in contact with a whole new set of colleagues across the U.S. and Canada interested in preparing future faculty.
The book then led to my current "extra" activity, managing the Tomorrow's Professor Listserv , which is a biweekly posting on issues in higher education sent to over 14,000 subscribers around the world. In this case I approached the newly formed Stanford University Learning Laboratory  about their buying some of my time--in effect giving me a grant--to produce the Listserv under their sponsorship.
Now I get paid for reading articles and books that are sent to me gratis by publishers all over North America. Of course I do more than just read these articles and books, I also make choices about what to advance on the Listserv, keeping in mind the very diverse audience. I also work with a student assistant so that the written reviews/abstracts and other materials are prepared well for distribution.
As a result of my editor/publisher duties, I have come to understand that different disciplines have different resource requirements, operate under different sets of constraints, and are subject to differing research and teaching reward structures. Furthermore, it gives me a much broader view of the issues facing universities in general, not only across the United States, but also around the world. This increased understanding helps me in my current role as a science and engineering administrator, in which I often have to interact with department chairs and deans in other schools. It has also enabled me to expand my seminar to include students from across the campus, not just those in science and engineering.
I can't begin to describe all the contacts I have made beyond Stanford as a result of the Listserv. From scientists, educators, government agency officials, to graduate students and postdocs, I have been exposed to dozens of interesting new people and activities, some of which will no doubt lead me to even more new opportunities.
I have many more experiences along the above lines that I have not mentioned here. The common theme in all of them is that these writing and editing projects are connected to my primary activities of teaching and research. They are what I call "high-leverage" activities that also served to broaden my interests in science and in the higher education enterprise as a whole.