Optimism is not only contagious, but can be truly beneficial in handling difficult situations. Positivity should not be confused with naiveté, but rather an appropriately positive response to an adverse situation. A bit of realism is healthy, but be sure to put a positive spin on it!
Patience is a virtue that seems to be less and less present in today's "I need everything now" society. That does not mean that one should ascribe to that mindset! Patience is often misunderstood as the act of waiting, but in reality it is much more than that and takes intentionality, practice, and extreme discipline. The benefits to be gained by practicing patience far outweigh the inconvenience of wasted time. Here's a great article from Psychology Today on The Power of Patience.
Persistence is often the difference between success and failure. We will all inevitable fail at multiple things in our lives, but those who approach their goals with persistence are more likely to meet their goals. Of course persistence needs to approached with a degree of discernment, because it is important to understand when to throw in the towel.