Of course the real trick is to make yourself so attractive (inside and out) that the girls come and ask you out.
Make sure you stay in shape. Watch how much you eat. Start a weight training program. Even if you are clumsy and not good at sports, you can still stay fit.
Practice good hygiene. Shower daily and use deodorant.
Pick up a guitar and maybe take voice lessons. Try to write some poetry and ask your English teacher for HONEST criticism. Don’t write it about yourself and how miserable you are.
Work on your mental health issues with a therapist. If you don’t feel like you are making progress find a different therapist.
Relax. You’ve got a lot of time for this.