Remember above when we identified that Houston uses the notes 1, 3, and 5 more in the chorus than the verse? Those notes are hierarchically more important, and so they appear in the most important section of a song: the chorus. The chorus is hierarchically more important from a structural standpoint, so part of the reason this song is so effective at creating a memorable musical experience is that it joins predictable notes with their predictable placement in the song.
At this point, your vocal should be sounding pretty good. There should be no noticeable frequency problems, leaving you with a very natural-sounding performance. Next, you’ll want to focus on adding color and character to your vocal using additive EQ.