I was like you,I cann't speak with girls nicely,i only talk when they are asking me something.I also felt uncomfortable,when i was around girls.But now,i have lot of female friends,Thanks to Members of AA they help
me a lot to over come this problem.I also like you to give advice.
1.Girls like to talk.First,when you meet girls in schools,colleges,etc just say "Hi.","Hi,How are you?" etc.But when she responds ,you must look at her.In facebook just sent messages like "Hi","Good Evening" etc.But if she doesn't responds your message,she might be busy.If she responds your message you must respond her.Second time when you meet her smile at her.
2.Girls like a boy with self confidence .I had gained my self confidence , when i talk with my mother,sisters,aunts and my neighbor.
3.Once you had made friendship with girl,you must know her likes,and dislikes.This will help you a lot to get closer to her.
4.Try to do meditation or self hypnosis for 15 mins or 30 mins.You must hypnotise yourself to build your masculine confidence and to increase your tetestrone level.This will help you,when you are around females,you will feel comfortable and you can approach any female and can start a conversation.You can also download hypnotic tapes from Miss Jacqueline Powers from youtube.
5.To impress a girl you must help her a lot.If she asks you to do something,you must do.Please don't show your smartness in front of girl.If you show,she might think,you knew more than her.
I am sure if you would try to follow this this advice,it will help you a lot.