There are three power-ups that are given randomly every 100 to 150 points scored. Save them until they can be used most effectively.

-3 power-up
Removes the bottom three lines of the board. You can then focus on removing a few colors on the top. Use it when you have at least one column growing very high and you need extra moves to clear tiles.

Stop power-up
Removes a match without a new row appearing. Use it when you have to remove a single tile from the board.

Target power-up
Removes all tiles of the color you tap, allowing you to trigger combos and clear the board. Use it when you have a lot of tiles on the board and select the most useful color to remove.