You are asking a question that has been asked 100s of times on this forum, with 100s of different answers. You can use seeds from a plant that hermied, you can buy feminized seeds, you can add this and that, and keep the temps low, or add banana peels to your seedlings and everyone will give you a different combinations of yes do that and no that wont work.
The best way to get the most females is plant more seeds. Other than that, good luck with that holy grail.