How to give talks
template using beamer for slides in LaTeX.
Section 4 of "Writing Mathematics Effectively" (Eric Rowland)
Your talk at the conference (Tanya Khovanova)
slides of how to give talks
Chapter 11 of the Handbook of Writing for the Mathematical Sciences, Second Edition, Nicolas Higham.
Giving good talks, (Satyan L. Devadoss)
Giving talks online by François Bergeron and Maria Gillespie
If you have an ipad or tablet you can prepare handwritten slides using apps like GoodNotes or Notability.
How to read math papers and slides
How to write mathematics?
How to write a clear math paper (Igor Pak, UCLA)
How to tell a good mathematical story (Igor Pak, UCLA)
Guidelines for writing mathematical proofs (from Ted Sundstrom's book Mathematical Reasoning Writing and Proof)
How to write mathematics effectively (Eric Rowland, Hofstra university)
Advice on Mathematical writing (Keith Conrad, UConn)
On writing (blog entry by Terry Tao, UCLA)
Ten simple rules for mathematical writing (by Dimitri Bertsekas, MIT)
The Mathematical Association of America awards several prizes for mathematical writing.
In particular, the articles awarded the Mathematical Association of America's Chauvenet Prize, Allendoerfer Award or Halmos-Ford Award are particularly worth reading.
Many other papers in the American Mathematical Monthly, College Mathematics Journal, or Mathematical Intelligencer (available via UMass library) are interesting and accessible to mathematics undergraduates.
At a higher mathematical level, the winners of the American Mathematical Society's Steele Prize for Mathematical Exposition have produced some excellent work.
The magazine Quanta from the Simons Foundation has many very good articles on mathematical (and other) topics, with a bias toward recent research. It also has good biographical articles, for example of the Fields' Medalists.
Some articles suitable for high school (or younger) audiences: https://www.mathgiraffe.com/blog/relevant-math-articles-to-share-with-teens
The book Mathematics Form and Function by Saunders Maclane (UMass library) is an excellent overview of mathematics at an advanced undergraduate level.
Mathema blog, a blog by Dr. Tai-Danae Bradley who works at X (formerly Google X) originally created to explain concepts to transitions from undergraduate to graduate mathematics. Dr. Bradley also hosted the PBS Infinite Series