How does one 'get into' Journalism and Column-writing?

Bit of careers advice and general interest here. I'm curious as to how one 'gets started' in journalism and column writing - it certainly isn't as straightforward as walking into the office and handing in a CV (or is it...). Bascially, if a would-be journalist/columnist thought "I'd like to write about [insert meaningful or interesting area of writing]" or just wanted to write for a paper, how would they go about bringing themselves to the paper's attention and making someone important thing it would be worth paying them big pounds to hire this person for the writing of...things? What exactly would an editor be looking for in the journalists he or she considers hiring?