Opening a table, were a chair is empty:
Hold over the chair, as if you are going to take it.
You: "is this chair taken?"
They: "no"
Sit down at the table.
You: "so what is the subject"
Opening at the bar, if she is standing alone
You: "Hey, where are you're friends?"
Her: "they're sitting over there"
You: "would they mind if I borrow you for a while?"
Her: "erm..."
You: "It'll only take 2 secs, I just want give you a test"(or whatever routine that wroks for you"
Some thoughts on opening
Two openers that I use regularly. The main opener isn't the most important part though. It what you do when you get something thrown back at you, that matters.
Sometimes they will be open towards you, and willing to talk. Other times they will throw shit tests at you.
Use all information/reactions she throws at you to your advantage.