Well these are common literary techniques you could use:
Symbolism
Juxtaposition
Repetition
Figurative language-metaphors, similes
Tone (everything has a tone so this could be like a last resort)
Imagery (but it's too basic by itself so tie it in with something else e.g. coastal imagery, dystopian imagery)
Allusions
Characterization
Rhetorical questions
Visual:
Salient image
Vector lines
Use of colour
Positioning
Body language
Contrast
Idk how to explain this properly but it's not the technique itself you talk about - it's more about how the use of it was significant in conveying ideas about discovery. So you really have to have a good grounding of what the text is saying about discovery then you just link these ideas to techniques that the text used.
e.g. The picture of the Eiffel Tower reveals that cultural discoveries can be catalysed through an engagement with unknown landscapes shown through the positioning of the persona below it with an inspired facial expression, suggesting the idea that their travels has widened their outlook on the world around them.
Like don't get too wrapped up in what techniques you use but focus more on explaining the
effect of the technique used because you won't get marked down for using one technique over the other (unless you only use basic ones) so you really have to have a good analysis.
Oh and my old english teacher told us that the secret to short answer is bs. You just have to bs it - chuck in some techniques, explain them and just make it sound good even if the idea is totally weird - as long as it's supported you'll be fine
