I am looking for some always applicable ways to get to know a women's approximate height.

Please spare the trivial "just ask" answers ;] It is trivial and i am especially looking for subtle ways.

One example I used with good result was:

"You look like a sassy girl. I bet you are trouble ;] (there's a saying in my language that says to be small and sassy. It's not necessarily bad. ) I would even go so far as to say you are small and sassy, but at least you look tall ;P"

She answered with why I would think that and that's she's actually quite petite.

The example is quite sassy itself and I would be happy to know some less risky ways.

I am curious for your answers ;]