7.2But don't harmonize every single melody note

This is a common beginner mistake.

Imagine a melody:

C D E F G

You could technically choose a different chord for every note.

But that would usually sound overactive.

Instead, ask:

Which notes are structurally important?

Usually:

• notes on strong beats
• long notes
• phrase-ending notes
• accented notes
• repeated notes that feel important

Those are the first places to consider chord changes.