The most powerful time to persist is when you don't feel like it. Keep going, and the persistence itself will make you feel much better.
The most powerful time for keeping your expectations high is when those expectations are not being met. Persist in expecting the best, and in backing up your expectations with action.
When things are not working out, that's an opportunity ...for you to get busy working diligently and purposefully. When there's a difficult challenge standing in your way, there's meaningful value on the other side of that challenge.
If it seems you've run out of ideas, and you're being blocked at every turn, go ahead and step confidently forward. You have nothing to lose and everything to gain.
The energy, the resources and the opportunities are most certainly there. Persistence is how you prove that you're ready and willing to make the most of those opportunities.
When you're weary, frustrated and disappointed, you're also closer than ever to the goal. Persist, and get yourself all the way there