Tips by Kathleen Sauerbrei: The important thing to remember here, (Level 16-3) is that while it looks like you can score a lot with one hit, the only balls that will give you points are the black ones and the skulls while dropping into the Cauldrons.
So be very careful with your shooters. You only have 21 of them. Getting one green Spider helps a lot and so do the Rainbow Bubbles as when you are stuck they will give you space.
You also might want to read the discussion thread on Level 16-3 where we where pondering on if the X or the O are better to drop first!
The Blogging Witches have this video Tips for a 3 Star score.