Why not learn from someone who has been there and done that? I've spent the last 21 years building a career in educational leadership. You might as well learn from my failures and from my successes.
What Not to Do (Or, What I did Wrong)
Don't make cold calls. I can remember being a 26-year-old teacher who was itching to enter the leadership job market. I made my one and only cold call to an assistant superintendent in a south New Jersey school district. I did most (almost all) the talking. My intent was to introduce myself and respectfully share my credentials for a potential position. The person on the other side of the line was, besides mostly silent, incredulous that I should pick up the phone and call a stranger looking for a job. I suppose you have to be careful with aggression in our profession.
Don't seem too eager. This maxim probably holds true in other fields as well. The more excited I was to make the leadership leap, the more rejections I seemed to incur. It's akin to my experience trying to find the right soul mate. The harder I tried to look for a lifelong companion, the less successful I was. When I least expected it, my current wife appeared suddenly. So, don't talk a lot about ambition and don't push or pull people in your direction. Let that first leadership position come along when you least expect it.
How to Build a Career (Or, What I Figured out Works)
Try to spread yourself out as much as possible. When people ask me about my career history, I warn them that I've been "professionally promiscuous." I started out as a high school English teacher, then took an assistant principal position in a middle school, moved to an intermediate school principalship, a high school principalship, a supervisory role for curriculum and instruction, and then the assistant superintendency. My perspective on teaching and learning is a cosmopolitan one. I've traveled around the field, and this has given me a big picture outlook on schooling. My ability to see both big and small (the details) has made me very marketable. Don't be afraid to take risks and move from time to time. Getting too comfortable in any one position will not help broaden your perspective on the field nor increase your marketability.
Do the grunt work whenever you can. As a young educator, I joined several professional organizations and never shied away from doing the nuts and bolts stuff that people couldn't do or didn't want to do. I created newsletters, developed websites, and organized meetings. Whenever somebody needed something done, I leaped at the chance to be the person to get it done. People will appreciate you if you are persistently helping them. Eventually they will see you as indispensable and will come calling down the road.
Meet as many people in the field as you can even if they stand on the periphery of the profession (over the years, I have befriended many scholars of subjects unrelated to education such as physicists, computer engineers, etc.). You never know when someone is going to bring up your name or how you might be able to connect to that person later in your career. The more you're out there involved in different things, the more people you will meet so that you can develop a vast network of mutually beneficial relationships.
The most important lesson I have learned as I worked very hard to build my career is to keep an eye on the process of helping people before keeping an eye on the acquisition of titles or financial benefits. Enjoy the ride first; take advantage of the "power" of the position second and a wonderfully satisfying and enriching career will follow.