Umm . . . I applied for a job at the airport news agency as a trainee journalist. They had a dark room, I took some pictures and discovered that I loved it. I've been freelancing ever since, working mainly for the Evening Standard and the Telegraph. I had a good combination of learning on the job and a bit of technical know-how.
Patience is a definite plus.
You also need to think about your assignment and get to know your subject - you should always do as much research as you can. My days start with a check of the long haul flights in Terminals 3 and 4. At the moment, the very early morning flights back from Sydney are worth checking because of the Olympics. Knowing which flights to check is based on the time of year - which spot of sun the celebs might be seeking, which festival is on where. You can glean a lot from the papers and from television as to who's due to be arriving when and from where.