I have always found that the best way to make friends, and by extension relationships, is to just work on yourself.

This means doing things like learning to be happy and comfortable by yourself first, then exploring your hobbies and interests and just being open about them on like social media or in a social setting.

Share the things you like, be receptive to others showing interest. Commonality helps bring folks together.

Beyond that just try to be sociable, don't try to force anything. Make a habit of talking to folks and eventually you'll find folks who share your interests and as a result you're bound to make friends.