Below are some excellent writing tips from very established scholars in various fields.
Ten Commandments for Scientific Publication, B. Ross Bamrish, University of Wisconsin-Madison.
Writing Tips for PhD Students, John H. Cochrane, University of Chicago
Ten Simple Rules for Mathematical Writing, Dimitri P. Bertsekas, MIT
A few Tips on Writing Papers with Mathematical Content, John N. Tsitsiklis, MIT
How to Write Mathematics, Paul R. Halmos
Tips on Research and Creative Thinking.
Creative Thinking, Claude Shannon
A Stroke of Genius: Striving for Greatness in All You Do, R. W. Hamming
Ph. D. Simulation Games by Mianzhi Wang.
A very cute game for simulating the road to pursuing a Ph.D.