I am qualified to advise here - I've been a music freelance for 22 years now. It is ever harder to break in as a freelancer - the world is full of people like you who want to write - the way to rise above the rest is a combination of ability and luck, combined with 'right place right time'
Start locally, and work for free. conact all local press within an area you can reach easily - reliability is going to set you apart from the wannabes, so make sure you can do the gigs you say you will. Qualifications don't matter - individual style and reliability do. make sure you pitch your copy in an appropriate style - no use doing 'Guardian' style for NME, or vice versa. other than that, you need to be very very determined inded. Best of luck!