At this point, given that you have a tutor, you should be expecting at the very least an improvement of a few marks. Since you have indicated that this has not happened, I would advise that you start writing timed practice essays as often as you can. By timing yourself under exam conditions, you will restrict yourself to using and training the most important tool in an English SAC - your mind!
The problem I notice with most students is that they rely heavily on external resources - thesaurus, teacher, tutor - and then fail to put that knowledge into practise. Studying is a very important aspect of good writing, however an examiner never gets to see your preparation. What they see is the final essay. By repetitively writing practise essays, you will notice that the background knowledge you have gained through your tutor will flow freely from your mind to the page. The more you repeat something, the easier it becomes.
So, as cliched as it may sound, practise essays under exam conditions are the best way to study. Good writing is a gradual process and requires a willingness to learn (study guides, reading through texts, highlighting phrases), and apply (Essay writing).
