Good luck w/ school! I think what makes a good nurse is having common sense and good judgement. You also have to be able to trust your own instincts, and you have to be a good listener, if a pt tells you something is wrong it probably is....
A good sense of humor helps also since we deal w/ life and death and serious situations, you need to be able to diffuse anxiety! Also being able to stay calm under pressure helps too, but that comes w/ time it won't be the first 6 months or even 1st year as a nurse.
Knowledge, experience, and the ability to apply it to reality, along side the practice of applying it to reality.
Compassion, even toward those whose lifestyles and choices we disagree with. This isn't to mean non-judgmental. As humans, we all judge even when we don't mean to. This means putting aside your own opinions and caring for people to the best of your ability.
Confidence and assertiveness, but not over-confidence or aggression. The understanding of the differences between those. Standing up for your patients, for yourself, or your coworkers depending on the situation.
Teamwork -- with other nurses, physicians, anyone working toward the well being of your patients. Nobody wins when you fly solo.
Work ethic -- making an effort to work. This doesn't mean you always get everything done. Some days you just have to pass things on to the next shift. It means you try your hardest.
I think understanding & operating within your scope of practice, being willing to say "I don't know", and being committed to providing competent care by continuously learning throughout your career are fundamental. I agree with the other posters in that care should be provided in a way that is as free of judgment as possible. I do think that, in addition to being a competent, qualified, life-long learner, having empathy for the people we care for really matters.
Also adaptability. You will be exposed to a lot of different situations in your nursing career and they may make you float to unfamiliar areas....so you will need to learn to adapt to those situations.
The good nurses take care of the patient. There are many ways to be a good nurse. We bring our own personal strengths to the job and we are all different.
The great nurses take this a step further. They inspire the nurses around them. They are a powerful and good influence on any unit lucky enough to have them. Their world is larger than just them and their patient. The greats have leadership and teamwork skills. If you have a great nurse as your charge nurse that day, whatever happens you won't face trouble alone.
As an aspiring nurse, in addition to everything mentioned above, I believe a great nurse takes it a step further and with humility and grace teaches patients about preventive medicine. A great nurse also stays current with new research and applies it bedside. I can not wait to devote my life to science.