Three ways to know new people.

Well, perhaps the best way to meet new friends is when you are doing  something new:

If you like to exercies, you  sign up to activities which you are with more people (gym, dance...) 

If you like to read, you would look a books group which it are in libraries, books shops, cultural center..., and not only you can to talk about books and writers, you can meet people littel by little, so you would do a true friends, you can  learn  something about their. So, you learn new something, in this way you meet other s people wich they have  the same like you.

What about travel ? do you like travel?, now there are several agency that it help you connet with others people.  

Other way is more easy, often you can meet new people in your rutine: talk your neighbours,  your cowalkers (don't talk about work).

Well, there are a few examples, but I'm  sure that you are thinking other ways. Try on.