To improve your tenacity:
Work hard and/or smarter. If you tent to be a clock-watcher who never works beyond quitting time no matter what, then you need to change your habits. Put in an additional sixty to ninety minutes of work every day by arriving at work thirty to forty-five minutes early and staying an equal amount of time after your normal hours. If you are someone who already puts in an inordinate number of hours, then spend some more tie planning to make your working hours more efficient.
Stand for something. To succeed, you must act with absolute integrity. However, if you can add to that the power of purpose, you will possess an additional edge. Write on an index card how your day-to-day work relates to your overall purpose. Then review that card daily to keep your emotional fires burning.
Make your work a game. Nothing feeds tenacity like our natural competitive nature. Try to harness that by making your work a game. Find others in your organization who have similar goals and create a friendly competition with them to motivate you and them.
From "The Maxwell Daily Reader," by John Maxwell