Easy, but don't let your guard down!

Your top priority is to eliminate blocks that can be cleared immediately. Instead of dropping blocks with a gap, dropping 2-3 colors that will fit in the next two or three spaces at once will mix the balls, allowing you to clear them more effectively and evenly. It's so easy that if you just drop blocks carelessly, you'll fill up and fail, so be sure to check the block colors in the order you plan to clear them! Then you'll usually clear it~^^