Short but a good explanation, though WA doesn't only use sound frequesncies to place a genjutsu on the opponent, in most cases physical contact will be used as a mean to convey the genjutsu, making it more difficult for the opponent to figure out he's under a genjutsu. That's also why every technique will be subtle enough to work, but also subtle enough t give to opponent a hard time figuring he's under a genjutsu.
Now, to get started I'd like you to his those can's over there
*Points to a row of 20 cans, all set apart with a distance of 20 cm*
You are going to hit those, with the whip only, one by one. You hit two or more at the same time, you set them all straight and start again, savvy?
One thing more thing, whip movements are mainly made by the use of the wrist, so try only using your wrist. In the future it will give your opponent less time to react, because by the time they can react, the whip is already heading their way.