Buy Hannah Montana albums. Get "Hannah Montana Soundtrack" and "Hannah Montana 2: Meet Miley Cyrus" and listen to the songs over and over. Get a feel for how Hannah Montana sounds.
Choose your favorite song or songs from the albums and practice them. A few of the more popular titles are "One In a Million," "Best of Both Worlds" and "Rock Star."
Pick up the beat. Sing with a lot of energy and enthusiasm. Unlike Miley Cyrus, Hannah Montana songs are mostly pop songs. Don't try to go rock or country the way Miley Cyrus does.
Keep the pitch of your voice between normal and high. Hannah Montana sings at a higher pitch than Miley Cyrus, whose voice is deeper.
Sound like a teenage pop star. Hannah Montana's voice sounds younger and more feminine than the more mature, almost manly sound of Miley Cyrus.