IOI - Indicator of interest. This is when the girl does something that shows she is attracted to you. For example, flicks her hair, restarts the conversation, asks you questions, laughs at you shit joke, smiles, gives you a playful punch on the arm whilst giggling (universal sign of a neg executed correctly), touches you, moves her body language to face you more, etc. Always match an IOI from her with one from you. The best way is to use kino to reward her for IOIing you i.e. touch her on the arm briefly whilst you make a point.
When you give her a verbal IOI this is often called "qualifying" her and should wait until the qualification stage (obviously) when you've actually found out something legitimately cool about her character/personality and you want to compliment her on it. An IOI like that should be folllowed with a little IOD to make it less awkward and you should never wait for her response, just move right along. E.g. "Oh you used to be in the band at school? That's cool cuz one of my main hobbies is guitar and I really get on with people who are musically-minded. Although that does technically make you a bit of a nerd
So did you ever play this song...."IOD - Indicator of Disinterest. If she gives you one, best to remain unreactive. Matching an IOD to an IOD will just end up with you two pushing each other away. You use IODs in multiple ways for different purposes. The first kind of IOD is a neg or false disqualifier. You use these to make her believe that you are not interested in her sexually and therefore she will let her guard down and you can fly in under the radar. One or two in the attraction phase is all that's required.
As mentioned above, IODs are also used as part of push-pull, where you match her IOI and then do a verbal "take away" and give her a little IOD. If you keep piling on compliments then you are no longer a challenge, so this keeps her interested and working for your attention. Similarly when kino escalating, you want to be escalating, then breaking off, then escalating, then breaking off again. This is the kino version of IOI-IOD-IOI, etc. and makes her want you to touch her again.