In part 3 of the speaking test, you should try to give longer, more detailed answers. A great way to do this is by giving an example.
However, I've noticed that students often forget to give an example, even when I've just told them to answer using the three steps: 1) direct answer 2) explain 3) give an example.
Here's the solution to this problem: when answering in part 3, force yourself to say the words "for example". When I force my students to say these words, they always manage to find an example, and the result is that they always give better answers. Try it: just force yourself to say the words "for example", and see what happens.