It can be triggered in a variety of ways: through touch, pheromones, body language, behavior, the tone of your voice, humor, confidence, and vulnerability. (Vulnerability is a really big one.)
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.
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. It could be a simple observation that she has definitely made about you.
What women find attractive is great hygiene and appearance. A man's style and degree of personal care is a huge part of what makes a guy attractive to a woman. Some women may prefer an artsy style more than a sporty style, but the important thing is that the man has a style more than which style he chooses to wear.
Symmetry: people whose faces are more symmetrical are generally considered more attractive. Averageness: faces that resemble others in the population tend to appear more attractive. Apparent health: people who look healthy, because of their skin and overall appearance are considered to have more attractive faces.
Smile and make eye contact when you see the person you like.
This will show that you're confident and self-assured, and it will also show your crush that you noticed them. If you notice your crush is looking at you, make eye contact and hold their gaze for a few seconds, then smile and look away.
Why we feel instant attraction to some people, and not others, is affected by lots of different things: mood, hormones and neurotransmitters, how alike we are, the shortage of other partners available, looks, physical excitement, and the proximity of geographical closeness.
Even if you're shy, try extra hard to look into his eyes while you're speaking with him. This will show that you're engaged and really listening to what he has to say. Listening to him, and showing that you're interested, is an easy way to flirt without making it extremely obvious.
Your hair is the most noticeable thing to a woman and usually it helps them decide if they really like it or understand it! Maybe because it's the topmost physical feature on your body.