-research the area you are investigating on google to find some good terms related to your coursework. eg - for texts you are examining in english, google some critical readings about the book itself, this should hopefully equip you with some useful vocab and words.
-contrary to what the person above me says, try to read more sophisticated texts. find words or phrases pertinent to your area of study to drop during essays.
-good vocab and dropping sophisticated words and english metalanguage related to your study in your essays can make an essay standout against other mediocre ones, as silly as it sounds. read sophisticated texts related to your set english texts and this will help improve your marks. particularly, english teachers invariably love sophisticated techniques. so research some !
best of luck.