First thing's first: start by reading through your research material and getting familiar with what you're writing about. Read through the text again, taking notes as you go, so that when you write something down later on it'll be easy for you to remember what it was that made sense to note at the time. Then take breaks if needed—anywhere from 10 minutes to an hour or more dissertation help UK—to give yourself time to process everything before diving back into the material again.