There are several common mistakes that are made on the exams. Some of them are poor time management, careless reading of the question, and poor use of diagrams.
One of the common mistake that I make during exams is the careless reading of the questions. I often make this mistake thinking that I’ve got the question firm in my mind. But, it is quite common that you really don’t have the firm idea of what you are going to write on the question box. So it is needless to say that you must read the questions carefully.