Riffs are a repeating thing. They come back to you. Some of the things on 'Back in Black' were ideas we had knocked around on tracks before that: 'That bit - maybe we should take a chunk of that and slug it in here.'
The thing I realised about composition is, we remember most composers for four bars of music. Four singable bars of music. Pretty much any major composer from Debussy to Ravel to Mozart to whoever else - you can kind of hum it.
It can even be a single note which defines the entire song.
Listen to any musical phrase or rhythm, and grasp it as a whole, and you thereupon have present in you the image, so to speak, of the divine knowledge of the temporal order.
My heart beats in three-quarter time.
I think no woman I have had ever gave me so sweet a moment, or at so light a price, as the moment I owe to a newly heard musical phrase.
And what, then, is belief? It is the demi-cadence which closes a musical phrase in the symphony of our intellectual life.
People say it's a bit repetitive to say, 'Oh oh oh oh oh oh,' but you can't translate the melody into words.
If I improvise vocals at an early stage of the song, I just kind of listen to the roll, and then I kind of have a little vocal hook.
I give 'em the hip, then I take it away.
Compose in the sequence of the musical phrase, not in sequence of a metronome.
Find one note on the instrument that pleases you, and then find another note that also pleases you.
Sometimes a musical phrase would perfectly sum up The mood of a moment. One of those lovelorn sonatas For wind instruments was riding past on a solemn white horse. Everybody wondered who the new arrival was.