I'm guessing because you're on this site, you might have a professional life and/or hobbies that skew towards the introverted and solitary, or at the very least are predominantly male-dominated. Ultimately you have to find activities that allow you to meet a more diverse group of people, and when doing so, project a general air of confidence and sociability. Keep doing it until it becomes natural, it may take years. Maybe you'll meet someone special romantically, maybe you'll just make friends. Either way you win.

If you're not working out, then start. It will help immensely. If you're not eating right, then start. These are the two most important things you can do, especially if you don't know where to start.

Leverage existing social networks - have friends who are couples? get to know them better, its possible they'll know someone they can set you up with.

Dating apps can work for some people but they can be an absolute grind and can leave you disillusioned and discouraged.

Don't resort to "tricks", don't "try" too hard, and don't think you have to become someone you're not comfortable with - just become the best version of yourself you can be, and just get yourself out there. Everything else will eventually fall into place.

Edit: someone mentioned improv - I would say this is 100% one of the best group activities you can do - they are inclusive, supportive, and have a diverse group of men and women. You will make friends, increase confidence, and be a part of a community.

Think of it like an investment. The more and longer you invest in your social life, the more rewards you will reap.