On writing and other relevant links therein, Terence Tao, 2007 >> worth noting the dual art on reading!

A few tips on writing papers with mathematical content, John Tsitsiklis, 2016

Ten Simple Rules for Mathematical Writing (see also the slides), Dimitri Bertsekas, 2002

Writing a Math Phase Two paper, Kleiman, 2000

Mathematical Writing (particularly the 27 rules suggested on pages 1-6), Knuth et al., 1987