Publishing is one of those careers that can take ages to get into unless you have a lucky break (usually being in the right place at the right time). I studied Sociology (it’s a myth that you need to have studied English Language/English Literature). After/during university, I did a few (unpaid) internships at various publishers until I managed to get a paid internship. I then got my first job as a Marketing Assistant for a non-fiction publisher and stayed there for two and a half years until I got a job in children’s publishing, where I started three weeks ago as Children’s Marketing Executive.
It’s mainly about showing your knowledge of and interest in the publishing industry and your chosen area (and not just your love of books) plus a mixture of luck and determination.