Most Helpful Guy
You are going to have to go to one of their concerts, fight through the mobs of people also wanting to meet One Direction, and if they are signing autographs at some point you may be lucky enough to get one from them and say a few words.
However, to be a realist, it is going to be incredibly difficult for you to even get close to them. They have a lot of swarming fangirls still.1
Most Helpful Girl
maybe go to one of their concerts1