If you're interested in helping your students gain some grit and perseverance, you're going to have to put in some effort. Sometimes through the pounding over the head method of teaching and sometimes with a bit more subtlety. Because unfortunately, you can't teach these traits in one single lesson plan with a quiz and letter grade at the end. So we have compiled some suggestions on how to instill some tenacity in your students.
Verbal Encouragement
Instead of general praise (i.e. you're so smart), recognize a student's performance based on their effort. Try saying, "Great job on that test! The time you spent after class reviewing really paid off." Students need to understand how their efforts effect their outcome, whether it be success or failure.
Resist the Urge to Offer Hints
Letting students struggle a little to answer a question will be a hard task for both you and your students. However doing this not only teaches them that it's okay to not always know the answer, as it's an opportunity to learn, but it also lets them become comfortable with the struggle. Just because it's not easy, isn't a reason to quit and give up.