That said, I'm looking for feedback from people on what topics they would want to see in a general strategy guide for a game like this. I will be including a section on game interface and more concretely formulating what the 3 phases of the game are (see the pinned chess article in this thread for reference), but what game concepts did you as a player find really useful to realize? What did you learn to manage that let you increase from difficulty 6/6 to 7/7? or 7/7 to 8/8?
If you don't want to write a "How to Win" guide, I guess what's left is the "how to think about the game" guide.
I'd say the two topics that helped my game improve are the concept of "Less is More", and long-term planning. These two go together, actually.
Because AI War is different that most RTS games, in that you cannot afford to just go hog-wild with conquering everything, you need to pick the important things. That means learning to form effective fleets using only what is necessary, rather than everything available. This helps the player get strong while the AI stays weak - "Less is More".
Closely associated with that is long-term planning. Picking out all the systems you need to take, and figuring out how to take them, whether to keep or abandon them, and how to do it - that's the planning. And the goal of the planning is to get as much as possible for as little cost as possible.
Radiant Phoenix has given an example in his post - Even before the game has started, he's already plotted out where he intends to place his stations, where he'll defend, where he'll expand to, and how he will approach and attack the AI Homeworlds.
A fully explained example game might be useful - Detailing exactly why each system should, should not, or might be captured. If some other players are willing, we could all do an in-depth discussion of the same game - but that probably belongs in a different thread. In the mean time, many of the AARs of high-difficulty games will show examples of successful strategies, and most players will explain at least some of their decision making process.
Of course, this (the low-to-ultra-low AIP style) isn't the only way to play. But as you move up in difficulty, it becomes more essential. At 10/10, you won't last long playing inefficiently. Of course, you usually won't playing optimally either, but that's just AI War.
Also, Kahuna's turret placement guide is a MUST to reference for how to defend your planets. Without learning the important techniques there, you can do everything else right and still get killed because of an unlucky wave.