You think you might hide it from the world (even from the person you're attracted to), but your body language says it all. Those vibes, coy smiles, long stares, everything from your head to your toe convey your emotions and inner feelings. This is a great way to find out if a person is interested in you or not.
The eyes have it all, and thus if the person is not interested, he/she will keep looking out the window, watching other women/men.
Lip and Mouth Activities
A girl might bite her lip gently, or run her tongue along her lip to show that she is interested. Some girls even do this deliberately to flirt, although it rarely looks natural. If you're a girl, don't try it, unless you're really sure it looks natural.
Fiddling and playing with hair is one way to show that you are interested. Girls wrap their fingers in their hair. Guys run their hands through their hair. Note that twirling your hair is more a sign of boredom and distraction.
Women normally like to sit cross-legged and note that it doesn't mean that she isn't interested. So forget about that and concentrate on the toes because, toes tend to react to general body energy.
So if someone's feeling bored and listless, they might just lay there. But if someone is feeling excited and energetic, the toe might make little circles or bounce. Woman, when interested, point their toes towards the man.
The way someone talks and especially the tone of the voice is hugely important. It will instantly tell you whether they bored and weary, whether they are thoughtful and quiet, whether they are enthused and interested, etc. To find out whether the person is interested in you, first watch your own speech and then watch how their speech changes.
If someone wants to 'get along' with someone else, they naturally match their speech patterns together. If you're interested in someone, you start to speak like them 'naturally', using the same tone of voice, the same loudness/softness and speed, and the same phrases even.