Staying on course comes from a combination of persistence and course correction.
I don't want to reward behavior that leads me away from my stated goal. Yet... when I'm going in a new direction, I'm going to fall short of my goals from time to time. If I fall short frequently, or by a large margin, I risk feeling discouraged to the point of despair and hopelessness. "I'm NEVER going to get it right!" It can be hard to remember at times that if I give it enough time, if I am consistent, if I try (that is, make the attempt) I will get there. If someone catches me in one of those moments of discouragement and tells me I'm throwing myself a pity party and get on with it already, girlfriend, I might feel even worse; withdraw, isolate, and cut myself off from others who have done it - who might give me encouragement and hope.
I think the word "try" gets a bad rap. I tried to waltz 500 times before I finally did it successfully. I tried to bake scones 50 times before I figured out how to do it consistently. People learn better when they are relaxed, curious, experimenting... Think about it - will you do better on a test in a quiet room where you can focus and concentrate, or with someone standing right behind you, looking over your shoulder, saying, "Are you sure that's right? Where did you get that answer? Aren't you done yet? You should know this! Haven't you learned this yet? What's your problem?"
Most people who are trying to [insert personal challenge here] have failed numerous times before. That critical, negative, inner voice is already turned up to HIGH VOLUME. What they need to build - to strengthen - is the "You can do it!" voice. The one that says, "The past does not equal the future. This time will be different. Keep going. You will get it. You will succeed."