To do math, of course every one always finds some interesting problems and then try to solve them and then publish them as articles. In particular, in doing PhD, thesis advisors normally give some problems to students. But I would like to ask a general question that "How can one find problems?". It is particularly useful for beginning graduate students (like me) without having research experience to find out some problems for her/him.
Thanks you all in advance for sharing your research experiences.