There are three ways that I know of. First off you can be lucky. That’s not very interesting so let’s move on.
Second, you can work at a customer-facing job. Guys working as waiters and baristas and bartenders never hurt for female attention. You can join a band, girls love guys in bands.
Finally, you can work on yourself. Work out, be fashionable, pursue hobbies, study human nature, develop your individuality. It’s a life’s work and if you keep it up, then even when you’re in your fifties and sixties girls will fawn over you. Be the most interesting man in the world.