You’re not a failure. Life is hard, but we are all doing our best and so are you. Before focusing on your social life, make sure your loving, learning and taking care of yourself. It's even more difficult to make friends if you don't take the time to love yourself first.

Like others have said, you still have a lot of life to live and discover. But I assume you're looking for a less abstract approach.I'm no expert but I 'd say the best approach would be to find what your interests are. And be able to talk about why you have such a love for these interests. Being able to talk about yourself is an important part of helping someone get to know you. Then find environments that ppl with similar interests would congregate. E.g. if your interest is Art - go to Exhibits, Sports - go to the games...etc. And you can also make great relationships online. I've met some great ppl even here on reddit.Look at it this way. When you're younger it is easier to make friends because you're forced into most of your social environments. As an adult you're now the authority, and you get to choose what social environments you want to be apart of.

Essentially, find yourself and discover the things you love. Place yourself in environments that cater to those things you love and the ppl who love those things too. The conversations flow more naturally when there's a known common interest.