Look to see how many marks are available and aim to write one point for each mark.
Don’t spend more time than the marks warrant (so if it is 5 marks, spend no longer than 9 minutes).
Leave a blank line between each point you make (to avoid the risk of the market not noticing one of your points).
Obviously, make sure you writing is easy to read – if necessary print your answer.
Read all the written answers in your Revision Kit carefully, and learn from them (but appreciate that the examiner always (deliberately) writes more than he expects from students.