Joe, I am going to suggest that the best approach is the direct approach. I think you should pick a friend that you know who is a guy. Ask him to approach a couple of the girls that you both know in common. Ask him to strike up a conversation with them that seems like he is concerned about you as a friend. It might go something like this:
I was talking to Joe the other day and he can't figure out what he is doing wrong. He has dated a few girls but the relationship fizzles after the first date. You have met him, what do you think his problem is? I would really like to help him. Be totally honest from a womans perpective and tell me is there something that you noticed that he should do or not do. What was your impression of him. I promise I won't tell him you told me any thing. I just think it would be good for him to know the truth because he really wants to improve his social life and make an effort to find a nice girl to date.
If your friend would do this for you, I can't think of any woman that wouldn't want to help. Be prepared that you might not like what you hear. Sometimes, when we can't figure something out it is because we are so unaware of what that something is that we are shocked when told what people think about us. That something could very well hurt your feelings and "try" to crush your ego. Don't let it. You obviousely are a very intelligent and nice person who is willing to make and effort. I am sure that effort will include accepting what is said and making the changes necessary. No one is perfect but the first step to perfection is finding where the flaws are.
Good Luck.
