A large focus of this rule set is on the physical presence of the commander.
First of all, the actual in-game settings:
[*] Set Custom difficulty level.
[*] Set 10-20 max camera distance from you. 10 is more realistic, 20 is not too bad and it helps sometimes when units are in difficult spots to click.
[*] Set Bare Map for map icons display level. To understand the situation you have to look around you, and move around to get a view. Press 'Z' to zoom your view in, as if you are using binoculars.
[*] "Set orders by courier at this level" appears to have a bug, so set this to Side for now.
[*] Do NOT check "Realism" in the settings.

The rules that are not inherent to the game but must be followed are:
[*] No in-game chat concerning battlefield information or orders.
[*] No ventrilo chat concerning battlefield information or orders UNLESS the two commanders are physically within talking distance. Basically, to talk in person you must ride your commander to the commander you wish to speak to. To facilitate this rule, all players should have disabled Fullscreen mode. This allows easy alt-tabbing to ventrilo and back to move to a separate channel to speak privately.
[*] All battlefield information and orders that need to be communicated must be done via courier or in person as described above.
You can of course have lively banter in ventrilo as long as you avoid communicating information or orders relevant to the battle. How strict this is depends on the players.
Apart from this there isn't any other concrete rule or necessary setting, as far as I know. After playing more I might add things. I've tried all these things in game and they were very enjoyable.
If you read these and understand them and like them, please post, that way everyone can know who's capable of it.