Try to make moves that will destroy the icing. This opens up space to make more combinations. If you concentrate on destroying the icing you will run out of moves unless you can make the combinations.
Keep on setting those special candies so it can cause a chain reaction. The colour bomb is very helpful as well when combined with a striped candy, or with a wrapped candy to remove 2 colours for a while to make collecting the candies easier.
Mystery candies spawn once every 10 moves, so take that advantage to open them up. Note that mystery candies can also contain chocolate, bombs and icing.