If you've got as far as your final year, you will be unlikely to fail. IME, most people who are going to fail do so in years 1 or 2.
Academic writing is a skill which some people pick up more easily than others. What I'd suggest is to find a few journals within your field, study the writing style used within those journals and try to emulate it. When I am writing an article, I will usually first decide the main section headings, then how I will break these down (subheadings) and only then, start filling in the gaps. Don't try to keep to the word limit whilst you are writing, try to focus on getting all your points down and keep on top of the references - don't fill them in at the end. Once you are happy with what you have written, only then start look at the word limit and start to cull your writing to meet the word-limit. It may seem heart-breaking to remove stuff you have sweated over, but ime you end up with better coverage of the topic than if you simply stop writing once you hit the required number of words.
Finally, a common mistake is to simply write Joe Bloggs (1990) wrote, "blah, blah, blah", whereas John Smith (2004) argued, "blah-de-blah-de-blah" without critiquing the work. You need to ensure that you are critical of everything you read. Don't take it at face-value. Why did Bloggs observe something different to Smith? Which observation, if any, fits with your experience and observation? How can you explain this? Where are the holes in the literature? How do you see your work/the field in general developing in the future? Why do you think this? etc