if there is a simple method to making friends it is seeing the same people at the same place(s) week after week. in some phases of life this is easier; ex, freshman year of college dorm. in other phases of life it is more difficult.
regardless, you have interests. other people have those interests. find people with those interests, that are fun, and also have space in their life for new people. do the interest together at some sort of location. then, invite the various people you've met over for a dinner party. voila- friends.
this isn't always a quick process, and it will likely be often frustrating and disappointing. its worth it though. the internet can help facilitate with meeting similar people who are open to friends.
specific things that have worked for me: going out dancing/club scene, internet(reddit/twitter), friends of friends, seeing movies, having people over for dinner.
good luck!