Original post by LaurasaurFor biology, as ribenas said, past papers are a very good way to go! I'd argue that application questions in biology are the most difficult ones.
Make an educated guess. Use what you have learnt about and keep linking it in with the specifics in the question. For example, a specification point might be to describe the synthesis of a polypeptide, whereas an application question might ask you to describe the synthesis of a certain protein they've written about.
If all else fails, sneak in as many key words (any biological words) as you can that link in e.g. Write about "complementary base pairs" and "sticky ends".
Write about things in excessive detail, you can pick up quite a few "any valid point" marks in long-answer questions.
Think before you write! Before you go into answering the question, jot down a few key words to summarise any ideas of what answer they are looking for. This gives you a chance to form some alternative ideas in those "suggest" questions and make short plans to structure your work. That way, if you have the time to check your answers, you can re-decide which idea was more likely to be wanted by the examiner.
To be good at these questions, you need a fairly solid understanding of biology. If you have a bit of time during revision, read around the topic slightly. Watch a khan academy video or a crash course biology video on YouTube about it. This can be surprisingly helpful!