Have you taken a IELTS test yet? If not, work on your writing and spelling. Nobody is perfect but having a good to great (not just barely passed) IELTS score can help.
The program I am in you have to have a minimum average of 60% to pass to next year. They want to see that you actually put an effort in to your studies and not just go through the motions.
VO wants to see that too or you will be classed as someone who will be coming for immigration purpose only, which means a rejection.