<p>Water drops don't need to be lighted directly, but indirectly.<br>
Try keeping some colored background paper in the back, set your flash to 1/64, point the flash directly to the paper and let it reflect back to the camera.<br>
Set ISO200, F/16, Macro Lens is a good idea to have (100mm F2.8 or something similar), Shutter speed does not matter, its the flash that will light the drop. So you can even keep the shutter open for 1/2 a second if you want, just trigger the flash at the right time.</p>