It's easy to over paint and over complicate water drops. I keep it really simple, paint the shadow (looks like a smile!) and highlight with one drop of white. I used a number 1 small round brush. Nothing else is really necessary; the drops are transparent so the color they sit on does not need adjustment. The more you paint and fuss with them, the more contrived they look.
This painting is 9"X12" Lindamccoyart@live.com for purchase info