What do I need to know about coloured ions?????Watch
I'd revise some of the more common ion colours just to be sure though.
Fe(II) is easy because it's always a green ppt
Fe(III) is always your typical brown ppt.
Cu(II) is generally blue but is a very deep blue with ammonia ligands.
Al(III) is always white but colourless with OH- in excess.
You only need to know about these 4 ions in the spec so I assume you only need to know about their colours? If you write these up on flashcards, it'll be ez to remember.
Edit: for AQA, you also need to know Vanadium colours.