Whether you are in class or at a bar, eye contact is a key part of getting a girl's attention. Glance at her, but when she sees you looking, look away. Repeat this and then hold eye contact for a moment and throw in a smile if you feel like its the right time to do so, then look away again.
Make your intentions clear. You don't have to say something blunt like, "I want you." Casually interject that she is "good-looking," or "stunning," or something along those lines to show you find her attractive. ...
In most cases, women are more attracted to men who can make them laugh. Funny men are sexier than bland ones. Seen as a sign of intelligence, a good sense of humour is instrumental in getting a woman interested in you. Don't be too serious, make her laugh and see how drawn she would be to you.
If you want a girl to go crazy for you, then you have to make her feel special by actually taking the time to recognize her as a unique individual. Tell her, “You're not like other girls…” or “You're so different from your friends…” and make her see that she really does stand out to you.
Your hair is one of the first things a woman notices about you. When a woman notices your hair, it's probably because you either have a great mane, or a lack of it. And neither of these could be a negative.
Respect and accept their decision. Put yourself in their shoes: if you'd just rejected someone and they kept trying to ask you out you'd wonder why they didn't get the message the first time.
She might pay some attention to get to know you better. However, as you communicated, the girl realized that she wasn't interested in you. If a girl ignores a guy, not answering, not responding, without getting in touch, then, most likely, she just wants to stop communicating.
When you spend time with someone and share vulnerabilities, it's easy to develop feelings of closeness and attraction. These positive feelings can develop into a crush, even when the other person is romantically unavailable. Traits such as kindness, intelligence, and a great sense of humor can fuel a crush.
This will communicate that you are interested in speaking to her. Keep smiling with open body language so she knows this is a friendly look, not a threatening stare. The longer she maintains eye contact, the more likely it is that she may be interested in meeting you.