1) Don't get shy while talking to any girl...because at that moment she also feeling same as you .....
2) Be very confident in front of her because most girl like that his boyfriend should be very confident while talking to her..
3) Try to show what you are don't over react in front of her.
4) If she is feeling in comfortable than make her comfortable....
5) Try to praise her beauty and thought..
6) Just talk in a very polite manner.
7)Show ur Funny side to her so that she can be friendly to uhh.
8) Place should be romantic .there should be less crowd.