I have stopped trying to take over enemy castles; it isn't required 
to finish the game and it doesn't seem to make all that much difference 
as to when the other players give in. I'm only on mission 11 though, so 
I can't really say for certain how much of a difference it makes. Also, 
I am so relieved to finish a mission that I haven't gone back and 
checked whether there is a difference. Still, I just ignore the castles 
and the computer player give in when they still have lots of 
land/huts/buildings.

   After the first few levels, inventory becomes a problem. The first 
shortage you run into is usually swords and shields (I am ignoring 
lumbar since it is really easy to set up and get going). Basically, once
I have an good area of land staked out, I try to get iron mines and gold
mines going quickly. The production of gold and weapons are pretty much 
decide how quickly I can finish a mission and everything else is a means
to that end. Kind of a vague strategy, but it is what I keep in mind.

   A problem that I used to run into was trying to build too much at the
same time and ending up with unfinished buildings all over the place 
taking forever to build (usually because lumber supplies keep getting 
depleted). And then when they do get built, it is always the building 
you don't need now that get built first; like a bakery before the farm. 
Anyway, just don't try to build all your food buildings, mines and 
smiths at the same time.

Keep in mind that you frequently start the game with 20+ coal, a pile of iron
ore, 10+ wheat, a few grain...I generally set things up so iron/gold foundries
and sometimes blacksmiths are completed before there are any mines to supply
them for this reason.  Usually I lay out all the mines and foundries, etc.
first, then connect the foundries with roads so they start construction;
I connect the mines as soon as the foundries' supplies have all arrived or
thereabouts.  This prevents the jams that can slow down construction so much.

Food supplies I handle differently, only because the time between a farm being
completed and it actually producing grain is so long; generally I start them
all at once and connect them immediately, and the windmill/bakery have just
enough time to process the wheat/grain in the castle before the farm starts
producing.

Usually, the first thing I do when I start the game is figure out where my
best farmland/land for big buildings is and deforest it.  When I start a game,
at least recently, I drop a sawmill, four lumberjack huts, and a granite-dude
or two before I've built two huts.  Often I find the most thickly forested or
rockiest land is exactly where I want to spread out; deforestation gives me
the room I need and the supplies I need.  In fact, in only one mission have
I built a forest ranger hut, and even then I didn't really need it.

Around mission 8 or 9, I had an extremely aggressive enemy sitting on the
second-best land on the map (right next to mine, the best land; fancy that)
and he was jumping the huts that guarded my best gold veins constantly.  When
he finally succeeded in taking it, I took it back, burned it down, and built
a tower.  Since then, when time isn't an issue, I tend to build towers when
I can, as they are almost unbeatable by identical troops when fully guarded.

(note: overrunning them is easy when the morale gets high.  So far I've not 
fought an enemy with enough morale to sneeze at.)

Using towers instead of huts takes longer, soaks up land that sometimes you
can't afford to lose (especially near mountains or on long slopes), but gives
you FAR greater defensive ability...and having four available knights rather
than two to attack speeds up the endgame tremendously.

I haven't tried this as I usually don't have a problem with losing huts, but:
I imagine if you _really_ wanted to reinforce a hut, you could destroy the
road leading to it and build a new one; this would cost you all the materials
currently in transit on the road, but it would also get all the damned
transporters out of the way.  Reinforcements for the knights that die in combat
still wouldn't be able to get to the hut, but they'd almost definitely run
into some of the waiting attackers, improving your odds substantially.

Other comments: there are times when the best way to guard land is NOT to build
a hut.  I've not had the problem myself, but I notice when overrunning enemies,
sometimes I won't be quite ready to tackle their castle, so they get to keep
the blacksmith sitting RIGHT next to it...until the poor AI starts feeling
vulnerable and builds a hut right next to the castle (note: this happens only
when I've cut the castle off from the rest of their city).  Boom, easy conquest
and there goes their blacksmith.  Keep in mind that you (and your enemies)
gain more territory by conquering a hut than by building one of your own.

One thing that might be of interest to someone: I was out of miners and picks,
and I had two iron mines and a coal mine without miners.  I also had two iron
and plenty of wood, so I built a tool shop and set the pickaxe priority to
maximum.  Tada, the tool shop built a pickaxe, and I ended up with a miner in
the coal mine.  Tada, the tool shop built a hammer (which by default is near
maximum on the priority list) and I was out of iron.  Ended up having to burn
down the coal mine (which by the time I realized this was full of food *sigh*),
set the priorities right on the tool shop, and start the coal mine over.
Don't let this happen to you. :)

The surest winning strategy I have found is this:
1. Clear out some good land.
2. Expand to mountains and find _gold_.
3. Figure out where your mines are going to be; at a minimum, a coal mine and
   two gold mines (I usually go two coal and three gold, coal seems to produce
   faster).
4. Find a place to put the bakery, with the windmill nearby, such that they can
   feed bread directly into the mines _without_ going past/into the castle.
5. Find another place to put two gold smelters, preferably without using the
   same road as your food supply.
6. Lay another road to feed gold straight into the nearest storage facility
   (I rarely build warehouses, but if you do, it's just as good as the castle).
7. Drop two farms if possible, and feed the roads as straight as possible
   to the windmill.  Keep in mind that the less zigzagging you do, the more
   land is available to the farmer; you can afford steep hills here to avoid
   switchbacks.
8. Make sure there's a road from your mines to your castle and from your bakery
   to your castle; this way the excess has somewhere to go.
9. Ensure that everything critical (mines, food supplies, and foundries) is
   WELL defended.  Again, towers if possible.
10. Leave.  Go to work or to bed, whichever.
11. Come back eight hours later.  You'll have a horde of messages; some will
    say you've been attacked, some that mines no longer produce (these are
    repeated periodically, so expect duplicates), several that because of such
    and such building you've lost some land.  Scan through these, burning down
    mines that don't produce (and kiss that food goodbye; I wish there was a
    way to tell mines to drop their food at the road before going up in flames,
    but I haven't found one).
12. Check out the knights menu.  Your morale will be incredibly high (expect
    200%+; I usually get somewhere in the 300%'s, and last game I came back
    to a whopping 617%).
13. Attack.  Attack everything you can reach, one knight to a target.  If it's
    a castle, attack with more than three but less than ten.  You will win
    almost all of the fights; expect a 5:1 to 10:1 kill ratio in your favor.
    Most of your troops will be captains, as you haven't got supplies to make
    new wimpy knights.
    If your enemies didn't attack much while you were away, or if they've got
    only one or two knights in their huts, you can safely turn the bottom
    setting of _every_ building-range-staffing-thingy to "minimum".  I do this
    without bothering to look around and haven't regretted it yet.  It makes
    a massive difference in how fast you can attack.

Notice that nowhere in there did I mention tool shops, iron mines, iron
foundries, blacksmiths, etc, etc, etc.  At least in the first ten or twelve
missions, there are enough supplies to get by; the supply of swords and shields
you start the game with is usually enough to handle 40-80 knights.  When you
can take a castle with losses of one or two rather than 20 or 30, you don't
NEED any more weapons than that.

Note with regards to available knights: the more efficiently you guard your
land (using small numbers of towers, ideally) the less knights are tied up
in defense.  This may seem obvious, but for several of my first games I built
more huts than I really needed to hold my borders.  Sometimes while advancing
on an enemy I will burn down huts just after I take them (checking for gold
first, of course) just to free that knight up.  Sure, he's gotta walk all the
way home first, but better that than hold a hut that guards empty land I'll
never utilize.

If you prefer to avoid the eight-hour-idle strategy, and thus don't have
overwhelming motivation when you attack, I've found this to be extremely
effective: your first targets should be, in no particular order: 1. Huts
between you and the enemy castle. 2. huts that, when captured, will burn down
enemy warehouses. 3. huts all around the enemy castle.

When you isolate or destroy all the enemy storage facilities, they will find
themselves unable to create more, expand, etc, etc, etc.  They also can't
train soldiers worth a damn.  Even if you're not ready for a real strong
offensive, isolating their castle alone can damage them more than any other
single action.

Oh, almost forgot: go for their sawmill too.  I've noticed wood has to go all
the way back to the castle before it comes out to be used, but I don't know
that this is still true if the castle is unreachable.

These are just my thoughts after having played the game for many hours, and
looking forward to many more.  This is one of the most addicting games I have
ever played, despite its flaws.  I heartily recommend it to anybody who hasn't
got it yet.  Ultrasound support is great, it's beautiful in SVGA despite my
poor 15" monitor; on my setup, though I need a boot disk, it runs flawlessly
without crashing or garbling sound, etc, etc.

I've found two bugs to date:
1. I noticed the same problem somebody else has mentioned: occasionally the
   game will "forget" that a building doesn't quite have all the supplies it
   needs, and not deliver lumber.  The same solution mentioned by the other
   poster worked for me: change the demand on that road by adding a
   construction project or simply wiping the road and building a new one.
2. One time while suffering the major shortcoming of the strategy outlined
   above (running out of knights), I was madly demolishing huts I didn't need
   and suddenly couldn't demolish anything anymore, including civilian stuff.
   I'd special-click the destruction icon, it'd ask for verification; I'd
   click ok or the checkmark or whatever, and it would make its little mouse-
   click noise, exit the menu, and not burn it down.  Annoying.  I had two
   knights left anyway, though, and that turned out to be enough to pass the
   victory threshold.

Questions:

Does anybody actually use the attack-with-weak-knights default?

Has anybody found the 'sending messages to yourself' thingy mentioned in the
manual?

Has anybody got a crack for this thing?  I've seen the settlers crack; it
doesn't understand my version (SSI).

Has anybody ever played a game with a more poorly written manual?

Can anyone verify or deny this: whenever the feather-helmet dudes (corporals?)
are fighting each other for a building (not in the open somewhere, I mean),
whoever gets the first hit always loses.  I've noticed this but I can't be
certain it's true, since sometimes the blood splotch appears directly between
the combatants *sigh*.

I had another question but it escapes me now.  Ah, the horrors age visits
upon memory...

I hope some of the content of this overly long post are of use to somebody,
and I look forward to getting some other peoples' comments or tips on this
game.  Sooner or later I need to abandon the eight-hour-idle strategy, but
when I go to bed or to work I always say to myself "what the hell, let's leave
it running and see what happens" }:)

Good luck to everyone just starting with this game, and have fun.  Oh, and
be careful not to have too much fun watching your little slaves work to
remember something important...