It's hard to start down a new path. It's equally difficult to continue on it once you stop. Even writing this little bit is something I have to will myself to do after taking a break, so I speak from personal knowledge, sharing the wisdom I have learned so that you might benefit.
Self-help books, videos, and the like often tell us to just keep on going. Alas, it isn't always that simple. Telling someone to do something is, in fact, less helpful than our modern world would have us believe.
Instead of telling, try showing. Show that you are fallible, yet your failings do not define you. I can pick yourself up and keep moving, and I'm no better than any of you. Thus, simple logic dictates that you can do the same. Whether that's getting back to a weekly writing series after a month away or persevering through a job hunt that lasted three years and took you to the brink, it doesn't matter. What matters is how you react.
That's not to say everyone can succeed simply by going on. There are times that trick won't work. A paraplegic can't persevere himself into walking again. No amount of hard work will make you a billionaire if you didn't already have money. Natural disasters care nothing for human endeavors.
But those are exceptions, not the rule. In most cases, while fighting forward won't always give you a victory, it will move you closer to that victory. More importantly, the act itself can be its own goal, because inertia is a powerful force for humans. Once we begin something, once we make it into a routine, it becomes much, much easier to continue.
This is why exercise regimens work or fail. The same goes for diets and fasts. And we can extend the principle into mental tasks, as well. Writing, for me, is one instance of inertia: now that I've stopped writing regularly, I find it hard to start back up again. For you, it might be something else, but you'll know it's there. Why? Because you're human, the same as all of us. I'm not unique in that sense, and neither are you.
So my advice to you—as much as this is an advice column, which it really isn't—is to find ways to overcome that resting inertia and get to the other half of Newton's First Law. An object in motion tends to stay in motion. Even if that object is the human brain.