While playing a level, you can see the berry you're about to shoot in the cannon, as well as the next berry in Rico Raccoon's hand.
It is possible to swap these two berries if you'd prefer to shoot the next berry first! Simply tap the berry in Rico's hand; this action will swap those two berries.
As your berries drop, the berries that you're firing may have colors that are not relevant anymore. Fear not! There is a simple way to fix this: simply swap the berry and it will automatically change into a useful color!