What is the best way to get marks for artist research?

Give each artist a double page spread in your sketchbook. Note down key characteristics of their work and the process of how they make it, it helps to decorate the page in the style of the artist and sticking in pictures of works that clearly demonstrate the characteristics you picked out. On the next few pages, do your own work based on the style of the artist, making sure you demonstrate your understanding and make it clear to the examiner that that's what you're doing.