How can I write more academically?

It takes practise and there are some good books on how to write academic papers.

Having a copy of a 'style sheet' which is actually a book or booklet helps, as well.

You need to know what your instructor wants you to use in terms of 'style' - your school/college/university book store should have style sheets or texts on hand and the requirements vary sometimes from discipline to discipline - faculty to faculty and sometimes even instructor/marker to instructor/marker.

As you run into marking of papers you do not understand or you want to improve on, take the paper back to the instructor/marker after making an appointment - make sure the person knows you are not questioning the mark but want to know how to create better presentation papers in the future.

One major and most difficult thing to do when writing one's first series of essays is to remember to let the instructor/marker know where you stand as seeing things from the evidence presented in your research. Do not research papers last minute. Do your research and have all the 'raw data' you want to use figured out early on and let the information simmer and cook in your head for awhile so when you do write the paper it is more your 'own' based on the research you are demonstrating to have done through quotations and citation of sources.

Never be afraid to ask for help - especially from a marker you can trust - even taking papers you have done for others - if that is okay with them.

Read a lot of high quality journals and articles.