Hi,
i'd like to give you some of my thoughts, from my own experience. The first thing I notice from your email is that you seem to 'need' a girlfriend. That is already a disadvantage. Ok, nobody likes being lonely, but a needy person is immediately unattractive. So you need to try and rid yourelf of that, or at least work hard to keep it under wraps. The second issue that you mentioned yourself is your shyness, possibly only around girls? That's another thing that you seriously need to work on.
I was just like you, I used to sit around feeling sorry for myself (not trying to be harsh with you, but you know what I mean) and wondering if it would ever happen for me. And I would be miserable and restless and it was horrible. But the longer it went on the more I started to see that I was not exactly presenting the best package to any possible partner. So I made a conscious decision to work on myself, for myself, before trying to sell myself to others. Sometimes the harder you look the less you can see. Often the best things come along when you aren't even looking. But that's not to say that you shouldn't put yourself in the best position to welcome these opportunites.
Basically you need to build your confidence as confident people are always more attractive. Don't fear embarassment or knock-backs, everybody experinces them at one time or another. And you need to appreciate your own value if you ever expect anyone else to appreciate you.
Luck and timing always play a part in finding a relationship so try not to be too pesimistic about it. Ok, so there are those stunningly attractive people out there who find it easy to attract others, but the vast majority of people are not so gifted. So we rely on our other qualities, which are often the more valued qualities anyway.
Don't give up...