To start with, you can make use of the fireworks to beat the level, as when activated they are highly likely to hit the level goals : apples and pears.
One of the main advantages of this level is that there are only a few types of pieces at play in the middle, which makes it easy to create power-ups despite the walls. Try to play several moves ahead and make matches below — it increases the chance of getting auto-matches above. Pay attention to the apples and pears counters: switch to the pieces you feel you are lacking in advance. Combine your power-ups by exploding them together so that you charge the Rainbow Blast faster.