There's a lot to say, so I'm gonna make it as short as possible.

I basically just wanna know what this girl is thinking and what techniques I should use with her.

Some of the things she's said:

-I don't like sharing a lot about myself
-I don't like talking a lot because then I come off as a flirt
-I'm quiet around people I don't know
-I have to click really well with someone before I let them in
-I can't be hurt. When my last bf broke up with me, I wasn't the least bit upset


What her best friend has told me:

-She's picky, guys work hard to get her
-She's not interested in a relationship
-She's innocent
-She never talks about her feelings
-She's different to any other girl

She's very inconsistent. She goes from showing a lot of interest, to practically ignoring me.

Use what her best friend told you about her as a opener/fake cold read. she'll be impressed with the observation, builds instant rapport.
then as you said your a flirt, what the hell is wrong with that? if shes innocent just try and keep the dirty flirtin from spilling out, there is such thing as clean flirting (i think lol)
hope this helps

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