Make sure you get the details right in your story. So if you write about a man with brown hair, green eyes and a limp for example, make sure you don't change that up in your story where suddenly he has blonde hair and blue eyes. So keep rereading your story and see if the details are correct throughout your story. A helpful tip, when you are forgetful, is to write down any detail in an excel file or in a separate word file so you can always check the little details. Detail is also there to make the story more interesting for the reader. He or she has to picture what he/she is reading, so detail can help out with that.
Anyway, good luck with your writing!