Starting Bubbles: 55
Recommended Potions: 3 holes in the ceiling and/or Rainbow Bubbles (recommended by Arwen Else Gris)
Recommended Potions: 3 extra holes in the ceiling, 7 extra bubbles at the beginning (recommended by bubble-witch-saga.se)
the Charm of Shattering
Points needed for 1, 2, 3 Star:
Doom Skull Bubbles
Try to burst an even line of bubbles at level 91 to break down the Crystal Bubbles, then continue your progress by trying not to burst the Spider bubbles and by dropping clusters of bubbles for points.
If you don’t yet have the Magic Potion Rainbow Bubbles and would like to use it, you can go back and play lower levels for more Stars. You gain the possibility to buy the Rainbow Bubble when you have 130 Stars.
If level 91 feels very frustrating and the bubbles seems to stop before you hit the ceiling, use 3-4 lives more and then you are ready to play for a Star by using BOTH the Magic Potion 3 extra Bubbles in the ceiling and 7 more Bubbles in the beginning.
Skillgaming also brought us a great video walk through for level 91. Thank you. :)