In the key of C, the root note is C, the major third is E, and the dominant note (or the ... we can use a note within a 3rd of that note in order to create a harmony that ... your goal is to bolster the melody and not compete with it you will be just fine.
Music consists of three main elements—melody, rhythm, and harmony. While the first two are typically accountable for making a piece of music memorable—think of the opening motif of Beethoven’s Symphony No. 5, or Timbaland’s synth lick on the Jay-Z song “Dirt Off Your Shoulder”—it’s the third element, harmony, that can elevate a piece from common and predictable to challenging and sophisticated.
