Is your game working? Is she diggin' on you?
Five signals she will say yes:

Letting you control the conversation can simply mean she lets herself get quiet. Most men who are insecure about asking women out assume when she's quiet, she has lost interest.
It may simply be your turn to open up. Don't, not yet.

What tactic should you take then? Nothing. Feel no obligation to say anything to her. This is where asking questions makes you more interesting and interested. Posing a question puts you in the driver seat and gives her the chance to become your passenger.