So, a lot of people, I'm sure, are unsure how to make friends in cosplay. The truth, honestly, is that it's really quite easy to do. Most cosplayers are willing to network and become friends with people, rather quickly and rather easily. If you go to a Gathering, for example, whether it's at a convention or just at a local park, the first and easiest step would be to simply walk up to the person who's in charge and strike up a conversation.
This could be a problem if you're a shy person, which I know many cosplayers are. So perhaps you should bring a confident friend along to help introduce you to someone. Sometimes a cosplay gathering will do a Meet & Greet where everyone can introduce themselves and get to know a little about each other. This is a good time to find members of the group that you might want to become friends with.
Another way to become friends with people within the cosplay community is to contact them through Facebook, Tumblr, or any other form of social media. Some cosplayers are really open to making friends online, some are not, so don’t get discouraged if some are unresponsive, and remember to be respectful.
If you see a cosplayer that's cosplaying one of your favorite characters, or is cosplaying a character from your favorite movie, comic, anime, or manga, simply walk up to them and strike up a conversation. Nine times out of ten that person is likely as passionate about the subject matter as you are. I mean, they did cosplay as the character for a reason. There are some people that just cosplay because they like how the character looks, but don't let that deter you. Most of the time, you will find people passionate and willing to talk and become friends over Star Wars, Marvel, Batman, Power Rangers, Naruto, DBZ, etc.
In short, making friends within the cosplay community is no easier or harder than making friends any other time. Now, if you simply have a hard time making friends in general, you may have a tough time, but do not let that discourage you. I, myself, have always had a hard time making friends. But ever since I became a part of my local cosplay community, making friends has become much easier, especially when you don't need to guess about what you can talk about.