A theme or issue question doesn’t vary hugely year on year. The angle is slightly different but the fundamentals remain the same. This came up in 2015:

Compare this to 2013 (it didn’t appear on the 2014 paper)

Referring to the marking scheme for these and using The Great Gatsby as an example, these are the things that your answer could address:

• approach to theme/issue by author and/or reader may be… cynical, dissapointed view of the decayed moral values
• focus on aspects of a theme convey a negative/pessimistic/positive/optimistic view… negative view of the hollow upper class
• narrative voice, key scenes/moments contribute to an impression… contrast the narrator’s character to the hollowness that surrounds him
• characters’ motivation/beliefs/behaviour, etc. affect readers’ impression of a theme… the importance of money, they idea it can buy love and happiness 
• impact of language, imagery, symbols, visual and aural effects upon readers: impact of language (imagery, symbolism, visual and aural effects) shapes perceptions… is Dr T. J. Eckleburg representing God staring down at them?.. What must he be thinking?
• plot, narrative voice, characters’ behaviour provide thought-provoking insights… Daisy’s beaviour versus Gatsby’s idea of Daisy
• key moments/scenes offer revealing considerations/perspectives… how does Daisy and Gatsby’s meeting reveal more about the characters?
• lasting impression is formed by the conclusion/resolution of a theme/issue… this your chance to say what you think of Gatsby’s death – why? What does it all mean?

Best of luck!