This refers to the ways a composer develops their ideas. To talk about the compositional devices, you need to hear individual ideas (motifs) and listen to how they have been changed or developed.
Can you identify the main motif ? Identify smaller motifs that occur throughout the song.
Some of the things a composer can do to an idea/motif (can be a short idea, or a longer phrase) are:
Repetition
Sequence
Imitation
Embellishment
Variation
Inversion
Diminution
Fragmentation
Transposition
Development
Phrase extension
Tempo change
Metre Change
Ostinato
Using technology – loop pedal, digital effects like echo
Piano – Broken chords or block chords
Guitar - strum techniques, harmonics, picking techniques