Well, if you were seeking for a short answer, I would say that main characteristics of humanism are curiosity, a free mind, belief in good taste, and faith in the human race. This is my opinion I formed out when studying this question. Still, if you need a comprehensive research on it, I would suggest looking for a few articles on the topic, or research papers, for example in the database of StudentShare. For this topic is kinda broad, you need to form out your own opinion on which characteristics of humanism are crucial and necessary. Make your own list based on the research of the topic.
Also, to start your research on a good note, find a selection from Corliss Lamont’s book The Philosophy of Humanism. I think he sets out good points as to what Humanism is about.