Talk about what's going on in the moment, make observations. And talk mostly in statements. Being witty and lighthearted helps as well.
Your main problem seems to be putting the other person on a pedestal, as soon as you're one on one. You seem to be using your group as the basis of your own value. And without it feel unconfident and low value (compared to the target).
The ultimate solution is "being in the now". There's an excellent post here about it:
natural-game-being-present-and-in-the-m ... 37458.html
and Eckhart Tolle's, "The power of now" defines it beautifully, albeit slightly "new age-y"
This'll give you the creativity and indifference to others' judgment, to fully express yourself, regardless of the situation.
Wolfus