Ground yourself deeply in your mission. Unite your mission with your personal, perpetual experience of the miracle of life. Couple it not with pain and tragedy. Celebrate and be thankful to be together enough to step out of your selfish self, giving yourself to others and the world. Feel your path as a rich, varied and uplifting experience.
Persistence is a byproduct of passion.
If you see persistence, passion is at work. To me passion feels like surrender, a freedom from doubt, a zest for pursuit. Try to live as close to your authentic self as you possibly can. It's redundant to say 'authentic self' because self is authentic. No more lag time for perspective.