She's Just Not That Into You

So y'all have probably heard of and/or watched the movie He's Just Not That Into You, yeah? Or maybe you've read the book. I haven't done either actually. Lol. Just haven't got around to it. I know the general gist in the book and movie is to show women the tell tale signs to look for when a guy is not into you i.e. if he doesn't really dig you. Well, I'm a people watcher and many times I watch as a guy approaches a woman and tries to chat her up and I find it interesting that the woman gives all the signs that she's just not that into him and he is CLUELESS! She frowns, she looks away (mostly at her phone for example), she answers her phone, she hesitates when he asks for her number (a different kind of hesitation from playing hard to get if she likes him), and the list goes on.

Ladies, help the brothers out, please! What are some gestures you display when you're just not that into a guy. Guys, what signs, in terms, of body language do you look out for? Can you tell if a woman is into you or not?

This is how it usually goes: Guy approaches girl, girl scans guy for information (I read that it takes 7 seconds to determine if you're attracted to someone. Sometimes though some woman have scanned all the way to the altar to determine if he's "husband material" LOL.), if she's not interested, defence wall goes up, and most times, guy has no idea and this equals an unpleasant experience for the girl and a not-so-successful "catch" for the guy. At the Speed Dating event, for example, one particular lady looked completely uninterested. Perhaps she had scanned the room and realized that her "type" was not there. Lol. Cos, man, she kept frowning, would barely look at the guys during each "date". It was as if someone had forced her to come. Guess she didn't realize that the risk you take in attending such an event includes not always finding your "type" and that you have to be a good sport cos while you might not find what you're looking for romantically, you might make some good friends.

So, ladies please spill the beans, when you're just not that into him, how do you let him know either directly (by telling him straight up) or indirectly (through your body language)?