well, noting that this will be superficial,
I've never really seen any girl do it right, but I've always thought that black and hot-pink would make for fashionable wardrobe colors.
Stripes (horizontal moreso than pin) can often make me think a little more about a girl.
Also, a kind of low-key "hippy" look has always really caught my eye--earth-tone colors, knit rather than synthetic fabric; generally, clothing that gives a peaceful, yet non-invasive vibe.
Regardless, clothing doesn't mean a damned thing in the long run. Fashion can make for a hook, especially if you're unwilling to initiate anything yourself, but . . . for lack of better words, I think the most attractive thing for an INTJ to see his/her partner in is what is, by and large, *natural*. If you're uncomfortable, not good. If you like it, it should work just fine.