Who’s The Beatdown? – by Mike Flores

One of the most oft referenced pieces of magic writing, this article formed the foundation for understanding of role assignment for many players when it was first published on The Dojo. While the examples used may be a little tough to understand for newer players, the lessons it teaches are timeless.

Do As I Say, And As I Do Part 1 (Paywall)

And Part 2 – By Brad Nelson (Paywall)
Nelson takes a lot of shallow looks at topics such as challenging your assumptions before deck choice, how to test ahead of a tournament, why he plays midrange, how to use the information you have earned to make in game decisions and sideboard, and then some tips on bluffing.
Honestly, a little hard to read and get information from owing to its fractured nature, but worth the effort.

Traction – by Michael Majors (Paywall)

An excellent article on how, in modern magic, simply drawing more cards doesn’t necessarily win the game. Instead Majors considers activated abilities and simply having a board presence may represent more cards than a Sphinx’s Revelation. He also talks about play patterns based on planeswalkers, some of the best card advantage engines available, both defending them by setting up multi turn sequences and how a board presence may make playing one unattractive to your opponent.