I'd recommend reading the question and looking directly for things that answer the question, after that point it's about reading the extract and then considering how it could link to discovery. A couple practice papers would be a great idea to build speed and confidence, especially if your doing them under timed conditions.
Another piece of advice would possibly be to just learn the rubric in some detail, that means clearly understand what are the types of discoveries (sudden, unexpected, carefully planned, rediscovery, self-discovery, etc) and what are the outcomes of discovery (emotional, physical, creative, sudden and unexpected, new worlds and values) and then just practice finding examples in your unseen texts and tie them to those key words.
If you're getting caught up with time it could mean that you just need the extra practice or you'll need to consider making better use of your reading time and/or cutting some time off the essay or creative?
Hope this helps!
