23.80Practical arrangement plan
For a simple song:
Intro — 4 bars
Cmaj7 | A7 | Dm7 | G7
Verse
simple accompaniment
Between phrases
small fills
Second verse
richer voicings
Bridge
increase density / reharmonize
Final verse
more melodic freedom
Tag
repeat final phrase
Ending
Fmaj7 → Fm6 → C6/9
That's already a complete arrangement architecture.