Albert Einstein said " I have no special talent, I am only passionately curious ".
Being a scientist is a tough job, but contrary to the popular belief you do not have to be a genius to become a scientist. However, there are a number of things good scientists have in common:
Curiosity: Scientist are restless. Like a baby experiencing everything for the first time, scientists look at the world with a fresh perspective. They seek the answers for every question and if the question is answered, another question will rise right away. "But how? And why?" The constant pursuit of knowledge and the fascination by how simple things happen or work are common characteristics of scientists.
Patience and perseverance: Good science is slow. Scientific progress does not happen over night and film-like instant breakthroughs rarely happen. It takes time to hypothesise an idea, optimise the methods to test it, prove it (or not) and then publish the results. This can take many years, or sometimes decades to achieve. Being able to patiently redo the same but slightly different experiments over and over again, spending weeks troubleshooting and coping with failure is one of the most difficult parts of the job.
Creativity: Not only artists are creative. In fact, I was told some years ago that science and art were much alike but at the time I did not realise why. Scientists are seen as very logical and analytical people, strictly following protocols and the scientific method, in order to achieve a logic theory that explains their findings. However, whether it is thinking of a hypothesis alone or the methods to get to an answer, scientists require imagination to solve problems or answer questions. Furthermore, it takes a lot of abstract thinking to image how a cell or gravity works.
Honesty and freedom from bias: Although while scientists have an idea on what to expect from an experiment, they cannot be biased towards their hypothesis. Scientists need to be honest about their results, accepting if their idea was wrong and contrary to their believe, formulate another that fits with the results and report them. Cherry-picking results or manipulating them in any way is a very serious misconduct in science and leads retraction of the published article and maybe dismissal of the scientist from continuing a scientific career. Thus, honesty and ethics is the foundation of good science.
Critical thinking and skepticism: Scientists are very critical of others and themselves, after all they spend years reading scientific papers, learning to scrutinise them and to find flaws in a theory. Scientists are trained not to believe in something right away, but to ask questions first: Why were these experiments done and not others? Did they use all the appropriate controls? Is the theory bulletproof or it has too many holes to claim that result? Where is the evidence? How good is that evidence? Is this a good argument? Is it biased? Is it verifiable? What are the alternative explanations? Who funded the research? If you ever read a scientific paper you probably realised that for every sentence there was a citation backing it up, and that is because scientists have to provide proof of every affirmation they make that it is not their opinion or idea.
Communication: Research findings are useless if no one knows about them. A good scientist is as good at doing the research, as he/she is at communicating it. Being able to translate their research findings and discussing them with peers, explaining how their research is important in order to get someone to fund it, and ultimately being able to share it the people that will benefit from it, are key to a successful career in science.
A scientist cannot rely only in his/her intelligence, it is a group of various characteristics that make someone a good or bad scientist. But, most of all a good scientist must be also be a good person.