Bit of a rush job on the background, and still needs a bit of work to sort out the random reflections. With limited kit and for a first attempt with both water and a dark background (with no backdrop) was quite pleased with the result.
Taken on a kitchen worktop, I stood the glass on a reflector cover, black side up.
I had the 430EX on 1/8 power behind (and firing through) a white reflector to the left of the glass, and a snooted YN something flash on the second lowest power setting (I’m assuming 1/32), to the right. The snoot was a homemade one but did a good job of keeping the light off the wall behind.
Camera was on the tripod with a cheap ebay remote release. Water was poured from a normal jug, as I hit the button.