Here we have Hanayo, the rice child. She has two voices when singing; she has the voice before the anime, luscious and strong, and she has the voice after the anime, cute and more shy. But just because she's soft spoken doesn't mean she doesn't project. Try your best at trying either one of these  voices. 

When speaking lines, she's usually shy and quiet, unless she's screaming about idols. Or rice. She gets really loud and energetic about those, so convey that. Your voice doesn't need to be necessarily high like hers. Just have it be able to fit the original.