I can relate to some of your problems. When you are a virgin at 20+ most guys run away from you, because they really don't want someone who has no sexual experience. Yours case may be similar. That is why I wrote beginning is hardest.
Why do you think you have no redeeming qualities? You are surely not objective on this. Now I am going to sound like some "dear Abby", but this is my personal experience so... please, try not to think about relationships so much, find something you really love to do, music, painting, cooking, bicycle riding, hiking... whatever floats your boat. Find club or any places where people with similar interests meet and do not try to find relationship. Just enjoy doing what you like to do. Let people see you at your best! I did not have any friends until I was well in my early 20s, and I was desperate! I thought nobody likes me. Then I found that in my city there is a club of people who love comic art and also like to make it! I love comics so I joined. Those were my first friends. Now as a busy working single mom I am again desperate for friends but no time to join some club, but I would have to! And so should you. Don't think about it so much. I know it sounds like a cliche but when you stop obsessing it will be better.