I recommend the following books to all my students.

Bird by Bird by Ann Lamont

The Art of Memoir by Mary Karr

The Elements of Style by William Strunk Jr.

The first two are genuinely entertaining and great guides for the creative process behind writing. Both books also give more practical advice on how to handle criticism, find motivation and write compelling sentences. The Mary Karr book may also make you laugh out loud. 

The third book, Elements of Style, is more of a reference text. It may be dry, but it covers everything you need to know about grammar, formatting, syntax and style. And the best news: it’s short! If I find students repeating the same mistakes I will refer them to a page in this book, so I do really find it helpful if students buy this book.