Your Character: Dean Winchester
Canon: Supernatural
What appearance/behavioral cues might Thrawn be able to pick up on?: Some lapsed military training in his stature, perhaps. A hunter's eye when he's not being mind controlled or drugged out. Sharp reflexes. He dresses like someone who gets torn up pretty often and needs to hide the blood.
What are some ways that are especially effective in manipulating your character?: Threatening his brother is top of the list, but that will make him resistant as well. Playing on his self-worth issues and need to please a stronger male figure (read: daddy issues) is an easier route to faster obedience.
What is your character's taste in art, and what does that say about them?: Dean hasn't had a lot of use for art. He likes films a lot (even ones that aren't Die Hard). He's got the art taste of someone who would never find time to sit down and study it or wander around a museum. His art comes in two hour bursts on pay-per-view. He's not dumb, just uneducated. He could learn if motivated to.
Is there anything in particular you want him to figure out?: Dean's drive to please authority figures makes him a hell of a sub once he trusts (or is under the dubious control of) a dom.
Is there anything you do not want him to figure out? Nothing that would be readily apparent. He won't want to talk about his time in Hell or his torture apprenticeship, but if he's ever sleeping in Thrawn's presence, he could be witness to nightmares that come from it.
Anything else?: I think that's it. :D