I actually read a book when I was single: “How to Marry the Man of Your Choice”. It was written by a Cuban-American woman who was very politically incorrect. She stressed looking as presentable as you can wherever you happen to be, and being kind to every member of the opposite sex that you meet, whether you are interested in them or not. You can’t wait for somebody to knock on your door. You have to up the sheer number of people you come in contact with, especially if you have religious views that will rule out a lot of people. Mostly, though, the wake-up call that people need is that they need to reduce their list of requirements and practice being genuinely interested in real men, not some fantasy.
And yes, I took much of the advice and it helped me connect with my dear hubby.
A lot of the problem is due to unrealistic expectations and standards. It doesn't matter what kind of person you are interested in. What matters is what people are interested in YOU.
Open yourself to being approached by anybody, make yourself presentable, improve yourself as much as you can, show interest in anybody who seems to be a good and decent person, and then make your choice from the ones who display interest in you.