1. Lengthy eye contact. Eye contact maintained over a period of four seconds or more is unusual between casual acquaintances or friends, but not amongst lovers; and it can be rather intimidating, but if you are flirting with someone and they know that you could be flirting with them, they are sending you an explicit message with the power of eye contact! This could also come from somebody who hates you, but that is unlikely from a stranger.
2. Mirroring. If your posture tends to be similar to that of the other person and tend to do what you do at about the same time that you do it, they are either consciously or unconsciously developing a rapport with you. You can test this by subtly changing one aspect of your posture (the position of an arm, for example) and noticing whether this change is reflected in the other person during the next minute.
3. Where the body and feet are pointing. If you are with someone who is happy to remain with you at the moment, they will generally speaking have turned to face you. If the person wishes they were somewhere else, they will likely have turned away from you, even if they are facing you; look for the legs and feet pointing somewhere else, perhaps even towards a door. Note that this only applies where you are in a one-on-one situation, and doesn't apply between groups of people.
4. Leaning in towards you. Somebody leaning in towards you is displaying a definite sign of interest, possibly even excitement! This is usually accompanied by open arms and legs. Conversely, somebody leaning away from you, perhaps with their arms and legs crossed, is displaying a lack of interest. If they are leaning in towards you and you do the same, you can be sure that something more is likely to happen, because it is very likely to lead to the next stage!
5. Touch. Firstly, if you are close enough to touch easily then that's a good sign. There are several things to look for. Hands resting across a table, on your side of it, that are close enough to touch, typically from a woman, signify interest; she doesn't want to touch first, but she would like to be touched! Picking off a piece of lint from clothes, whether it exists or not, is another good sign. Touching upper arms when sitting next to each other where it is not especially crowded is often done. Lingering touches send an even stronger flirting signal!
6. Raising eyebrows upon first meeting. This is usually over very quickly, lasting about a quarter of a second. As it happens on first meeting, you need to be quick to look for this one! The longer it lasts, the more interest lies beneath, as it can last for up to a second.
7. They are looking at your face or body other than your eyes, especially your mouth or your erogenous zones. They are probably imagining what it would be like to kiss that part of you!
