It tooks mine like 3-4 years to become "dabbling" or some other very low level in any military stuff.
Tried with having a teacher dwarf, embarking with military dwarfs etc, nothing I could do really made a difference, tried in 3-4 different forts too and for few last versions of DF
Danger room = takes time to setup but once done in couple of seasons I have experts/grand master in whatever weapons and armor I give them.
Way easier than the planning interface too.
As for early siege, I usually embark in a place with sand (or I hack one soil to become sand if don't have sand).
One of the first industry I set up is glassmaking one, then makes buttloads of "green glass serrated disk" and makes traps with them.
Infinite sand = infinite amount of trap components, I keep a few dwarfs making them in auto-mode and once in a while make my mechanics plant more.
And Green glass is almost as deadly as steel traps components if I am not wrong, it cuts early sieges in small small small pieces.
My entry is always a long 3 wide corridor of traps that leads to the stairs going to my fortress proper, add a bridge/moat if needed.
2 dogs/cats/whatever pet that you won't miss at the entry make sure to spot sneaking enemies or ambushes so they get pwned by traps.
In the later years I do a circle of "watchtowers" with animal between glass windows to spot ambushes.
For later years defense, magma solves everything and no cleanup after.
I always embark near volcanos (more fun) so I dig a long long corridor as alternative entry to my fortress, block it in normal time with bridges.
At the Z level under that corridor I build a magma reserve that matches the corridor above.
Then on the entry level I remove the floor (so it goes into the magma)
Then replace the floor with retractable bridges that I all link to one lever in my dinning room
When siege arrive, I tell dworfs to go in, block the normal entrance with a bridge, open up my "corridor of magma doom".
AI see normal entry is blocked, goes to corridor of doom.
Once they are in, I pull the lever, all the floor/bridges suddendly disappear and the whole lot dive into magma under.
If needed, pull lever again, bridges come up, AI re-calculate path to entry, leftover go into the corridor of doom again.
Rinse and repeat.
Only stuff I can't kill this way is demons, flying monsters.
Megabeast are usually immune to magma but once in it I drop water in it, making it into obsidian, that kills anything
This post has been edited by Gormaz: Sep 1 2011, 10:33 PM