Should you ask her for her number or get some lunch when you can feel that the girl is not into the conversation? Is it that they're shy, apprehensive or waiting for you to make the final move?
So fuck it just go for it? Worse that happens is that she turns you down? How can you up your chances? Cause the conversation was so one sided. Nothing I can do but run out of material.
Ask if she has tried the coffee /tea / fruit smoothie from such and such place
you went there yesterday whenever and the fucken scones are to die for
we should go have a smoothie and discuss life the universe and everything sometime blah blah
any door of opportunity is meant for your foot bro
make it up as you go