I have a very low opinion of women. How can I get this rectified?

You should go to a behavioral therapist. There are so many different psychological reasons why you might be feeling the way you do, and a therapist could help you pinpoint these and help you to change. I had a very low opinion of men for years, and with the help of a therapist, I was able to overcome many of my biases and become more objective and less generalizing. I'm much happier as a result.