In order to elevate your writing to the academic level you have to be clear and concise. You don’t want to add words just to add words. Everything you write should have a purpose. To make it more academic, it usually involves deleting unnecessary words and being very specific.
University of Toronto posted a useful article on their website to help you understand when a word is necessary and when it is not. See the folowing link for more information:
Once you finish writing your paper and are ready for the editing stage, try the tips listed in your article when reading through your paper. You will notice a big difference in the way it sounds.