How to obtain field experiences? How to best build my portfolio for film industry?

Hello, I obtained a degree in non-arts fields but find myself really interested in film directing after graduation. My current job is completely irrelevant to the film, and hard to find group that shares similar interests. I have tried to direct some work on my own, but I don't know when it will be sufficient to build up my own portfolio? And how to get more field experience and learn from so?