Do's and don'ts when writing an academic book
There are many books and online resources on mathematical writing.  These range from style guides that deal with issues from type setting to copy editing to books that talk about mathematical writing at a somewhat higher level.   Here are a few of my favorite sources:

Nicholas J. Higham.  Handbook of Writing for the Mathematical Sciences.  SIAM 1998.  http://www.worldcat.org/title/handbook-of-writing-for-the-mathematical-sciences/oclc/697886419

Steven G. Krantz.  A primer of mathematical writing : being a disquisition on having your ideas recorded, typeset, published, read, and appreciated.  American Mathematical Society, 1997.   http://www.worldcat.org/title/primer-of-mathematical-writing-being-a-disquisition-on-having-your-ideas-recorded-typeset-published-read-and-appreciated/oclc/797735421

SIAM Style Manual for Journals and Books.  http://www.siam.org/journals/pdf/stylemanual.pdf