I'm constructing a list of articles here to direct people to debates and useful advice on their armies and more general strategy.

If you can think of other articles to add to this, please send me a PM. It's meant to be a fairly short list if possible though, so I will be selective.

General stuff

Know thy enemy

Mathhammer Tactica (or Warhammer Probability 101)

AP vs Rate of Fire

Denied Flank (and other battlefield strategies)

Evil Assault Tactics

Black Templars

Blood Angels

Chaos Marines

Chaos Daemons

Daemonhunters

Dark Angels

Eldar

Ragewind on Eldar

Imperial Guard

Tactica - Imperial Guard

Necrons

Necron tactics

Comprehensive Necron Unit Tactics

Orks

How to build an Ork army

Space Marines

Making marines work

Marine bike armies

The Tactical Squad

Space Wolves

Tau

The Darkside of Tau

Tyranids

Common Tyranid units

Witch Hunters