Do a full IELTS writing test.  Your Task 1 and 2 will be sent to two different examiners just like in the real exam.  Each examiner will give you a band score for each of the criteria and correct your mistakes.  They will then give you advice on what you need to do to get higher marks.   You also receive a Band 9.0 example essay for each task.  This is all returned to you within 3 days.  If your exam is soon then let us know.  See an example on our homepage.