To begin understand a simple truth: girls are not creatures from another planet, and the same people as you. They are as shy of you, just don't always understand the logic of action young people. But you will definitely learn to understand them, if you take control of your shyness.
Believe that you have many good qualities. Try to write your positive traits and from time to time remind yourself that you're a great guy. If you doubt that quite attractive in appearance, try to determine what exactly don't you like about yourself and change it. Insufficiently developed musculature? Work out. Unkempt appearance – take care of yourself. Wear only clean and ironed clothes, exceptionally clean and not worn shoes. Don't forget to get a haircut. Be careful always, not only when going to see a girl. Over time, this will give you confidence in their own attractiveness and become a habit.
Learn to be a good conversationalist. In dealing with a girl, try to be as relaxed as when communicating with friends. Remember that all people (and girls especially!) love to talk about themselves. So in the conversation, ask the girl questions about her, at first some trifling, over time, the stories you will be able to find new topics of conversation. Show a sincere interest. If I see that she speaks with enthusiasm about something, it means that this topic is interesting to her, and you should take advantage of it.
Remember that you can not learn anything if not to try. And with communication. Most likely, your first attempts to talk to a girl will not be very successful, but over time will get better and better. And without practice there will be no progress. In this regard, by the way, it is reasonable to train the skills not with those girls, which you have clearly expressed sympathy, with those to whom you are more indifferent. First, with them you will be able to control their emotions, and secondly, in case of failure, you have nothing to lose. In addition, much more useful in terms of experience, to communicate with those who don't have a lot of common interests. Learning to communicate with these girls, you will be able to communicate with any and they will cease to be ashamed of.