Best career advice I ever got probably came from my mentor, my theatre porfessor, Charles Dickens (yes, his real name), which was: know how to tie a tie, have a pair of black dress shoes, and be a good company person. The latter part of that advice, of course, was the most important. Which basically meant keep your nose clean and do your job, don't engage in backstage backbiting and intrigue, don't go wrecking company cars or trashing apartments when on the road.
I have always tried to adhere to this advice and found it kept me employable and re-hireable.