Hmm... Sort of a tricky one, my circle of friends I've sort of established through societies; or I happened to know them from before Uni. If you ever keep an eye on Facebook, then people often share events that are going to be happening. Also, most of the people I know from different courses have a class Facebook page or Whatsapp group or something, so social networks are a great way to stay in the loop, even if you're usually not a big user. I suppose if you manage to get over the first major hurdle, which is trying not to be shy when you're talking to new people, then the rest of it will flow naturally. Especially in the first few weeks, don't be too scared to strike up conversation with new people! If anyone is reading this in chatter, feel free to pipe in with some ideas!