Now if you want to write a song in a major key, you have to use chords that harmonize with the scale. The result is that the 1, 4, and 5 chords are major chords; the 2, 3, and 6 chords are minor chords; and the 7 chord is diminished (this chord is rarely used in popular music and I will therefore not be mentioning it again). So in C major, these are the chords you have to work with: C major (the 1 chord), D minor (the 2 chord), E minor (the 3 chord), F major (the 4 chord), G major (the 5 chord), and A minor (the 6 chord). The 6 note in a major scale is called the relative minor; that is, a major scale, beginning on 6 and ending on 6, is a minor scale in the key of 6. So if you want to play a song in A minor, use the same chords as you would use for C major.

If you haven’t understood anything I’ve said, don’t worry. Here are some common keys, the chords you can use if you’re writing in that key, and the number that corresponds with the chord (something you’ll need later). Key of C major: C major (1), F major (4), G major (5), A minor (6), D minor (2), and E minor (3). Key of G major: G major (1), C major (4), D major (5), E minor (6), A minor (2), B minor (3). Key of A major: A major (1), D major (4), E major (5), F# minor (6), B minor (2), C# minor (3). Key of D major: D major (1), G major (4), A major (5), B minor (6), E minor (2), F# minor (3). If you don’t know how to make these chords on your instrument, you’ll need to get a chord chart—they’re easy to read and they don’t require any knowledge of theory!

One last thing before we move on: time signatures. Most popular songs are in 4/4 or 3/4. The bottom number tells you what note gets the beat (e.g., 4 = quarter note) and the top number tells you how many beats are in a measure. Don’t worry too much about the bottom number; just pay attention to the top number. In 4/4 there are four beats per measure; in 3/4 there are three. The first beat is emphasized more strongly than the other beats. So in 4/4 you would count: 1, 2, 3, 4, 1, 2, 3, 4, and so on. In 3/4 you’d count: 1, 2, 3, 1, 2, 3, etc. "Row, Row, Row, Your Boat" is in 4/4 time. "Amazing Grace" is in 3/4.

Now that you’re thoroughly confused, let’s move on to writing the melody.