Try to find a site with a volcano, flux and an underground river/pool. Adamantine too, it's only present in mountain-tiles and even then one single spot per world-map tile.
The river/pool part may be optional, as you may not want underground plantlife growing in areas you prepare.
Can't remember if you had to flood&muddy the areas you want UG plants to grow or if they grew up normally in unmuddied UG soil tiles.
Training in 40d is done by traditional sparring and your dorfs will not hold back their punches. The wrestling tip was already told but anyway, wrestling also affects dodging in 40d so yeah, make legendary wrestlers first(they train up the skill fast as hell). Try to check that they don't end up holding clothes from their soldier partners when equipping, I recall they won't pick up weapons or shields if they have a spider silk glove on hand. Wrestling was also a lot better and a squad of 10 legendary wrestlers could do a lot of damage even if they had crappy gear. Still, make them some armor.
If you're handing out backpacks for food, do that after you're finished training them as wrestlers. Otherwise they can grab the backpack and the food ends up on the floor and it can't be moved anymore(it was claimed by the soldier with the pack, and they won't pick up the food again, they just replace it if there's a free backpack somewhere).
Economy can be "fun" if you bother with getting the nobles up to that part. I sort of miss it, luckily you didn't need to make coins to have it work. In fact, never make coins, the dorfs end up splitting the stacks of 500 a lot and they end up everywhere, making hauling take more time.
Injuries that make a dorf unable to walk put them permanently in bed in 40d too, so either be prepared to lock their door and let them starve or end up with people who will never do anything more but be fed and brought water to. They only get out of the bed if they hit a mood, but end right back there once it's all done.