There is no specific way to start a conversation with a girl. One good way to initiate a good conversation with a girl is to first give an honest compliment, avoid cheesy compliments and stick to genuine ones. Say something nice about what you can see on her right there and then. It could be her eyes, her hair, her shoe, her smile, her dress… it could be anything!
After this, try to ask some open ended questions, this is where your ability to engage her in a conversation comes to play. You want to make her talk, so ask questions that will enable her to do so. Instead of asking “are you travelling for the holiday?” say, “what are you planning to do during the holiday?” A question that requires a detailed response keeps the conversation flowing as oppose to one that can be answered with a Yes or No.
Hope this helps.
The best way of initiating conversation with a girl rather depends on where you are and what the situation is. If you are both studying together, it is easier because you can make a statement about th study material and ask if she agrees, or flatter her by asking if she has understood it rather better than you.
It's a good way to get into conversation if you start by saying you found something confusing, or difficult and you may find she has felt the same. Then you have a mutual experience to start off a friendship. It might even be that you say with a smile, 'I found that a bit boring/really interesting, did you?' as you leave a class.
If you are not students, and you have not met th girl before you need tofind an introduction. This is a different question.