What are you studying in MH?
I don't recommend reading textbooks to provide most of your MH knowledge. In other words- DO BACKGROUND READING AND DON'T JUST RELY ON TEXTBOOKS. They're too superficial!
Anyways for WW1, I recommend you read the following books while taking down some brief notes relating to the syllabus. Keep in mind that you won't have time to read these until the holidays when your ATs for term 4 are over. Anyway-
Peter Simkins, The First World War, Osprey- this is the best book out there providing a succinct yet accurate account of World War One. It is easy to read and the author just gets to the point. The book also provides excellent maps and pictures and is split into sections of the Western Front, Eastern Front, Mediterraenean Front. It is too superficial though in its info on the home fronts.
John Keegan, The First World War, Penguin Books- a lengthy book, which I only recommend you to read after you have Osprey. Read only the sections pertaining to the Western Front (about 70% of the book) Keep in mind he gets a bit pompous sometimes in his writing.
H.P Willmott, World War One, DK- An easy book to read that provides a lot of detail for the average reader. Excellent in providing information about weaponry and sources. However, don't read the whole book. Only read sectiOns pertaining to the Western Front.
Good luck.
and remember that you get nothing out of World War One if you don't connect with what these people went through during that time.