Pick a finished song with a similar atmosphere, structure, or theme — and use it as a compass.
Pick 2–3 reference songs. Analyze: structure, length, dynamics, number of lines per verse, theme. Don't compare quality — compare craft.
Reference is not copying — it's 'learning from the masters.' Even Picasso copied before finding his style.
Dr. Luke used a reference track for every song he produced. Max Martin analyzed hits before writing his first.