Hey! I'm revising grade 8 theory super hard! I'll give you what I know and I can only hope it helps!
Cadences!Perfect ~ 5 to 1, dominant 7 to 1. Listen for the Tonic!
It sounds as if the piece has ended.
Imperfect ~ 1 to 5, 2 to 5, four to 5, 1b to 5 and 1c to 5. Listen for the dominant. It sounds unfinished and about to go on.
1b - first inversion
1c - second inversion - the bass note does not change!
Interrupted ~ 5 to 6, dominant 7th to 6 Superdominant stuff!
You think it should be perfect but it has a minor chord.
Plagal ~ 4 to 1
This is the amen chord. Think hymns!
Modulations! A change of key!Major key to:
1) Dominant - increases tension
2) Subdominant - decreases tension
3) Relative minor [minor third lower] - shares same key signature or sumin.
4) Supertonic minor [relatively rare]
Minor key to:
1) Dominant Major
2) Relative Major [third up!]
3) Dominant minor
4) Subdominant minor
Piece talk!1) Loud/soft
2) Staccato/Legato
3) Minor/Major/Atonal[no tone]/modal [lots of notes next to eachother]
4) homophonic block chords/polyphonic melodies [ i think of ring tones

]
5) Contrapuntal? Note against note..think Bach!
6) "Thickening" of the music? Gets fuller?
7) Baroque[Bach]/Classical[Mozart]/Romantic[chopin]/Contemporary[Debussy or Bartok]
I'm still learning stuff at the mo. A little [extremely] shaky on everything! I know how evil grade 8 aural is and to the point of ridiculous. Even some piano teachers can't tell the differences so why the ###### should we! And as for singing - we're PIANISTS, not SINGERS. I personally think more emphasis should be on piece playing rather than an aural test which most piano teachers either skip out or do minimal work for. Also, the jumps for grades in aural are absurd!! grade 6 I didn't have to learn anything and passed fine in aural...grade 7 was throwing me into the deep end and grade 8 is me drowning at the bottom of it!
Leanne xXx
p.s. and I apparently have perfect pitch..if you play a note I can recognise it. However, I still find aural difficult! I can't sing low...only alto-soprano. Stupid..stupid!