[Xietor]

Dedas posted this on another thread, it was enlightening:

If you have a mountain province adjacent to your capitol and your capitol has more than 2 adjacent other provinces, build a castle there. The peg-fortresses Ulm has are great with their 700 defense and admin 20, and they do not drain the capitol's provinces, only the province their built on. Read it up in the manual. There is "hidden" 50% resource pool in every province that is used for admin first. Building a castle on a province unlocks all the resources in that province of course.

A small walkthrough:
Let's say that the mountain province you have adjacent to your capitol is a mountain with 65 visible resources (if you capture it this number will of course go down at first due to the unrest). This figure (65) isn't too far fetched and is pretty standard for a mountain region.
After you've captured it you start building your castle here, paying the 1000 gold that you will have on turn 3 if you did everything right; if you have difficulties with this use an Alchemist pretender, or use one so you also can build troops in your capitol on that turn. The castle will take 4 turns to complete, so use your scout pretender to build it the first turn, recruiting a commander or scout to continue it on the next. Attack another province adjacent to your capitol (with good resources) with your unoccupied army.

This is what the new castle will get in resources:
65 base
*2 - for fortress built
30% bonus - your dominion
25% bonus - Ulm production bonus
= 201,5 resources
+ 20% from adjacent provinces without a castle.
Say 4 provinces with 45 resources each after your dominion Remember now that it draws from the hidden pool so this won't affect your capitol.
Total = 237,5 resources

Not too bad is it.
Your capitol will still have way over 200 resources as it begins with 130 (if you play production 3) and draws 50% from adjacent provinces.

Another good thing with this is that your new fortress is only one move away eliminating the dangerous travel later for your troops, who almost everyone has mapmove 1.

You could of course build a citadel (admin 40) if you only have standard provinces around you, but this would lead to draining problems later when trying to maximize outcome.

The strategy is to build a long chain of castles as fast as possible. Your capitol will form the center.

After you've built around 4-5 castles in the first year and a half and labs here and there, start mass producing troops and smiths.

You will find that this castle chain is not something your enemies wants to siege as you can ship reinforcements between your castles fast and safely. In your capitol you should build lord guardians for defense of the chain. In the other try to build one troop of each type useful for the campaign you are planning. The smiths should of course forge like earth boots with their earlier forged dwarven hammers (a final 50% forge bonus) and later good equipment for you commanders. Also build some siege engineers and siege troops (they have crossbows) with any spare resources. They will come in handy, I promise.