Level 65 requires you to get 8 lemonades, but only 2 lemonades can be present on the field at the same time. First, you need to get rid of the boxes blocking the middle and lower parts of the field. Thus, you will get more room for both matches and auto-matches.
The walls can be formidable obstacles for creating matches, so it’s best to save up your power-ups for when you have few favorable matches remaining. Multiple explosions at the same time will charge up the Rainbow Blast meter faster and clear the path evenly for both lemonade glasses to go down.