your lacking confidence. Major amounts of it. If you read through the relationship section a little bit you will find a post i made on boosting confidence. Its in somebody else's thread so you will will thread so you will have to look a little bit. But if you read through some of the previous problems, some of your questions and concerns may have been answered a bit.
It seems to be like you have some confidence because you already think that you are good looking. You need to think that. Think that you are the best muther fucka around. But don't get cocky.
Basically, if you just want to talk to a girl, just pretend like she is one of your guy friends. thats the best way to do it. DON"T TALK TO HER LIKE ONE OF YOUR GUY FRIENDS, but approach her like one. When you approach her talk about something relevant. Don't push it. It will just come. Maybe you will be in line at subway and you will tell the pretty lady in front of you that she made a good choice on the sandwich. the rest will just fall into place.
The best thing to do-- i know it may sound harsh or mean but--- practice on the fat chicks. if you can get comfortable talking to a fat chick, other girls (that you may have interest in) will be super easy to talk to.
Now i am not saying this because fat chicks don't matter or they are ugly and nobody like them, All i am saying is that usually, guys don't have attraction to fat chicks and that is why it is easier to talk to them.
The same thing goes for friends. Your not attracted to your same gender friends and that is why you can talk to then easily and make new same gender friends more easily.
people tend to go "OMG she is pretty" and that right there sets the tone for how the approach will go or how the non approach will happen.
be yourself. Be cool