Learning is essential and as such should never stop. Do what you can to broaden your horizons each and every day; learn something new and don’t forget to contribute to your respective areas and professions as well. Educate yourself formally and informally, get involved (attend conferences, seminars; read books, journals, websites…) and expand your experiences.
Do all of this with a strategic goal in mind – think of where you would want to be professionally in 3, 5, 10, even 20 years and then strategically position yourself to be successful as those years pass by (and they certainly will).