…twirls her hair?
I could be an IOI, or she could just be twirling her hair. A better judge is if she moves her hair to expose her neck in your direction, but hair twirls can be an IOI for sure. It’s a conditional thing.
Thanks, hey is there any website on that stuff? googled a bit and found this. Romantic body language
I had no luck ont he hair thing, can you find more on it?
Fast Seduction 101: Art of Pick-up and Seduction
This place should have some info for you. I’ve glanced through it before, but never looked in depth.
It depends on the girl.
Some girls twirl their hair all the time, because it is sexy and they want to be seen as sexy. It could be flirting, but some girls just like to flirt for fun.
If it helps you with your confidence see it as an IOI and think that it means, that she is totally into you. It will help somehow. 
Here is a web-page with multiple views on that. In the end it is meaningless.
I would go for unlimited confidence and believe that every girl is into you no matter what she does. 
That works.
Assume attraction.
Gem is right about not getting hung up on looking for IOIs. But playing with hair has the effect of dispersing her natural pheromones though she might not know who is causing her to do this (again, I’ve had some fun throwing this in to conversations).
In London the subway often has two long escalators parallel to each other going in opposite directions. Sometimes I will use this to demonstrate to a pheroskeptic friend - as you ride the down escalator each successive girl going the other way will adjust her hair as she encounters your sillage.
By the way if you wear insane doses of none, guys will do this too (less of a twirl and more a touch/light brush). Maybe it’s like unease with the strong competitive signature and trying to reassert their presence - I don’t know.
hmm..i’m gonna have to see if i can cath myself doing this. I honestly don’t think i do. Usually it’s someone else playing in my hair. I’m gonna start trying to be more mindful, so I can figure what my tells are.
What I wanta know is what does it mean when a girl repeatedly smells her hair? Does she want me right then and there or does she merely need a shower?
An IOI Factory!
You’re quite literally talking about an IOI Factory! Complete with conveyor belts taking hair flipping girls down the assembly line…
Hair twirling can indicate interest, but it can also indicate nervousness, boredom, or just be a comforting habit. Consider that the way hair feels can become associated with security through mommy or daddy. Usually, in my experience, it will be girls who twirl their hair a lot, and women who mean something by it.