I do the general things that make the most sense to me. I start by changing it around so I am humans instead of dwarves in the INI.
Then I do:
No digging or no digging past a certain level (until I do a dedicated tunneling project to find HFS)
Everything hand crafted from self made or imported goods (IE no trading of finished goods only raw materials when importing)
Workers follow a profession (no one worker does only one job with the exception of some like miners but instead have related jobs)
Every building made of blocks with the exception of wooden log houses
Every building has floors made of blocks
All constructions are made from uniform materials (unless aesthetically required)
All buildings must be made realistically (IE don't make a steel house or use materials that make no sense like orthoclase walls)
All buildings are built on the surface (with the exception of cellars and some underground storage in rooms no larger than 5 x 5)
No exploits like traps, danger rooms, locked doors etc.
Low population limit (enforces growth by natural birth and helps avoid FPS death)
All Military is trained through a drill instructor (IE the most veteran soldier runs a squad dedicated to training)
All Military has uniform equipment and until uniform equipment is achieved they are not battle ready
All Military squads are either specialized or generalized (IE a spear squad, sword squad etc OR all squads contain each weapon)
All raids/sieges must be fought
No underground farms and above ground farms are small plots that are planted in 1x10 strips with one space between strips
All farm grounds must be "cleared" before use (IE channel down one level)
Farms in Fallow mode for half the year (to help simulate yearly fallow needs as well as practicing crop rotations)
With the exception of some vegetables and fruits ALL food must be prepared as a meal before consumption
No trading of finished meals (only raw goods)
Proper and uniform grave site that is represented above ground. IE the bodies may be one layer under but there must be mounds or markers for each death. Separate the graveyard into separate sections even for soldiers, workers, and nobles.
Accommodate for population based needs (IE leave no noble positions empty and make a jail or other supporting structure as soon as its available)
I also try and build a castle and town separate. The town is usually outside the stone (block) walls of the castle and almost always only has wooden palisade walls (IE can not be walked on and is made of wooden logs)
TL;DR versionBuild/run things realistically and don't use exploits using the "Human" challenge as a base
http://df.magmawiki.com/index.php/DF2010:Challenges#RacesI love the little dwarfs and what not but living in a cave is WAY to easy
with this rule set I have found that it extends my game a great deal because I am not invincible in about 30 minutes or less...cause for me invincibility on command is the biggest game breaker for me (in any game)...and I am a big medieval buff that prefers realism