Along with providing sufficient lighting substitutes for my lack of external flash / spotlight, my other primary obstacle was getting the camera to focus just on the spot where the water drop would be. This first photo shows one of those earlier attempts. It's obviously blurred, but I like how the splash looks like sparks of fire or gold.
After several hours and various locations, backdrops, containers, and camera settings, here are a few examples of the (somewhat) satisfactory results! In order to get these shots brighter than the one above, I had to increase the flash compensation as well as the exposure compensation 1 stop. The light meter yelled at me saying that the shots would be severely underexposed, but I ignored it. I'm learning that sometimes you have to trick the camera to get the results you want.
Here are the camera specs for all three pictures below:
18-55mm f/3.5-5.6 lens
1/200 f/4.8 ISO 200 exposure compensation +1 stop
I had some fun in post-editing, applying various colorful filters. I liked the green tint to this one.
In future repetitions of this project, I will try using different colored backdrops (this one was blue, as you can see), and will also try a larger container to isolate the droplet without the peripheral vase edges and reflections.
Hope you like them, and let me know if you try this out! I'd love to hear about your techniques.