Kendra Gale got me off to a great start with Missy. The only behaviour I shaped that I had to change was "be nice".
The undesirable behaviour was bugging me for treats. Using Kendra's suggestion I taught her to "be nice" which meant turning her face away from me. Just as KG said, Missy would offer the head turning as a way of asking for a treat rather than crowding or nudging me.
That's great until I started thinking of her doing that in a halter class

! I stopped using "be nice" and started shaping for a respectful facing forward. That gave me control in head positioning.
I thought I didn't need "be nice" any more... until yesterday. I didn't need a show pose but she was begging. Just one, firm, "be nice" and she turned her face away. I immediately marked with "Yes, good girl" and rewarded with a neck scratch.
+R has helped so much. Missy shied at a flapping garbage bag the other day. Thanks to the +R work we've done I was able to walk her close to it and ask her to "touch" while pointing at it. She wasn't enthusiastic about it at first but trusted me and gingerly stretched out to first touch then gently nudge it. Success!