The University of Toronto has a fantastic array of resources that offer advice and help on academic writing . We strongly recommend that you browse their resources thoroughly.
Harvard provides predictably excellent (if slightly left-field) academic writing advice.
Meanwhile, Haverford College has aggregated some of the best grammar resources available from universities in the US. This is for students who would like some help with the mechanics of writing e.g. when to use semi colons, adjectives, prepositions etc.
If you want some light but educational relief then you should check out The Oatmeal’s grammar comics. They are entertaining, but most importantly, informative and helpful.
The University of Bergen gives an excellent step-by-step guide to writing your Masters thesis.