Make Eye Contact
It would be a great idea to refer to things that she already mentioned before, this way you will show her that you paid attention to what she shared with you.
Making the right approach might seem too stressful after all those romantic movies that you have seen. It is not going to be in slow motion in real life. However, do not let that stop you from coming up to her and starting a conversation.
Getting in touch (literally) is a great way to flirt with a girl, however it might be tricky. You definitely do not want to seem inappropriate, so try to find something that would lead to physical contact.