Maybe you're too nice?
I honestly don't know, really. The biggest problem I see with people who want to meet someone is they'll assume a bit too much about how it works.
For example, the Bristol trend for meeting someone is nightclubs, and pretty much nothing else. So, even people who hate nightclubs will go to them when they want to try and meet someone. But it almost never works, because the type of people they'll meet there will be the type who likes nightclubs, who A) will probably notice they aren't enjoying themselves, which lowers attraction, and B) would be a different type of person, meaning that even if there is a significant attraction, the personality types wouldnt match.
The best advice I could give would be to find something relatively sociable or potentially group orientated that you like, even if its traditionally male dominated, and go for it. You'll enjoy yourself, the people you'll meet will be enjoying themselves, and will be a similar type of person to you, and even if you don't meet anyone, you won't have lost anything.