Question time
What flash are you using? What lens are you using?
Firstly from lookin' at your current pics, I suggest you have your camera at the same level as the water in the bowl. Like such:
Camera --> |_|-.......\___/ <-- bowl - Instead of lookin' down on it. That way you get the best plane of focus for them. Some nice wrapping paper does wonders for bokeh and such. Also marbles or glass beads in the water are rather good. Different drop heights make a difference too, usually the higher you drop from, the higher the drop "spire" If you have a look through my pics theres lots of different ideas, like collisions, floating drops and such. Another important thing, is shoot in low light. Have your flash on the lowest setting that's realistic for what you wanna acheive, that way you don't get "blur lines" (or whatever real picture takers call them) from reflections within the room (lights and the like) I'm sure I don't need to talk about different apertures and their effects. Just remember its the flash, not the shutter that "freezes" the drop.
Anythin' else, gimme a yell. I'm always around.