An important part of getting inside a song is identifying what each instrument or voice contributes. With this information we expand our knowledge of writing and arranging.
On first listening to a piece of music it’s easy to miss some of the instruments used, when they make only a small or subtle contribution. But if there’s a sound in there, however minimal, then it’s making a contribution to the arrangement and we should know about it.
There are numerous factors we should consider. As you list the instruments, make some judgements about the sound, playing style/content, what they add to the arrangement and interaction with other instruments. So don’t just make a list, but describe characteristics.
For the sound of an instrument here are some words that you might use::

electric, electronic, acoustic, heavy, distorted, light, bright, mellow, distant, chorused, fat, thin, abrasive, soft-edged, fading, sustained, warm, metallic, hazy, clear, clean, dirty, real, sampled, synthesized.
any others?>>

For the style of playing you might use words like:

tight, loose, energetic, delicate, aggressive, emotional, staccato, fluent, gentle, simple, busy, advanced, bending, sliding, understated, live, sequenced, quantized, high, middle, low,
any others?>>>

For judging what each instrument contributes to the arrangement, try:

melody, rhythm, chords, harmony, pad, counter-melody, riffs, sustain, repetitive, fragmented, movement, off-beat, figures, broken chords, drone, close, distant, energy, stabs, held-notes.
any others?>>>

Look for the features (and descriptions) that best explain the characteristics of each instrument. Make relative judgements also – compare features with other instruments, or compare what an instrument does in contrasting sections of the song. Is there anything unusual about what you have observed? Be selective in your descriptions - describe crucial characteristics.